subject:"Re\: \[zfs\-discuss\] Best 1.5TB drives for consumer RAID\?"


On January 23, 2010 8:23:08 PM -0600 Tim Cook t...@cook.ms wrote:

I bet you'll get the same performance out of 3x1.5TB drives you get out of
6x500GB drives too.


Yup.  And if that's the case, probably you want to go with the 3 drives
because your operating costs (power consumption) will be less.


 Are you really trying to argue people should never
buy anything but the largest drives available?


No.  Are you really so dense that you extrapolate my argument to an
extremely broad catch-all?  There are other reasons besides cost that
people might want to buy smaller drives.  And, e.g., if your data set
isn't that large, don't spend money for space you don't need.

The post that I was responding to claimed smaller drives *allowed* him
to get to raidz3.  I challenged that as incorrect.  It's the larger
drives that *require* raidz3 because resilver time is longer.  So far
I've seen no argument to the contrary.  Just a side argument about
cost which I happen to disagree with.  And a followup side argument
about planning for redundancy which I also disagree with.

Let's say you need 3TB of storage.  That's a lot for most home uses.
The actual amount doesn't matter as the costs will scale.  So you
buy 5 1.5TB drives.  4 (2+2) in a raidz2 plus a hot spare.  For the
sake of this argument, let's say you've done the math and raidz2
meets your redundancy requirement, based on time to resilver.  More
likely, a home user has not done the math but that's besides the point.

Now let's do it with .5GB drives.  A quick survey shows me they come
in at about a 10% discount to the 1.5TB drives.  I'm being generous
because I can't even find .5GB drives, but I see that 320GB drives
are about 10% less.  If you want to get even cheaper, 250GB drives
are about 50% less cost than 1.5TB drives (which by my argument, which
you refute, makes them 3x more expensive but whatever).

So with .5GB drives you need 6+3 drives -- because the smaller drives
allows you to get to raidz2, plus a hot spare.  That's twice as many
drives, however you are only paying 10% less per drive.  PLUS with this
many drives you now need a pretty big chassis.  Plus your power costs
are now quite a bit higher.

Please put together a scenario for me where smaller drives cost less.


I hope YOU aren't ever buying for MY company.


Rest assured, I won't be.

-frank
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

On January 24, 2010 11:45:57 AM +1100 Daniel Carosone d...@geek.com.au 
wrote:

On Sat, Jan 23, 2010 at 06:39:25PM -0500, Frank Cusack wrote:

Smaller devices cost more $/GB; ie they are more expensive.


Usually, other than the very largest (most recent) drives, that are
still at a premium price.


Yes, I should have clarified that.

-frank
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-24 Thread Erik Trimble


Rob Logan wrote:

a 1U or 2U JBOD chassis for 2.5 drives,

from http://supermicro.com/products/nfo/chassis_storage.cfm 
the E1 (single) or E2 (dual) options have a SAS expander so

http://supermicro.com/products/chassis/2U/?chs=216
fits your build or build it your self with
http://supermicro.com/products/accessories/mobilerack/CSE-M28E2.cf
I'm aware of the Supermicro chassis, and, while they're nice, I'm after 
an external JBOD chassis, not a server chassis.


--
Erik Trimble
Java System Support
Mailstop:  usca22-123
Phone:  x17195
Santa Clara, CA
Timezone: US/Pacific (GMT-0800)

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

On January 24, 2010 8:41:00 AM -0800 Erik Trimble erik.trim...@sun.com 
wrote:

an external JBOD chassis, not a server chassis.


http://h18006.www1.hp.com/storage/disk_storage/msa_diskarrays/drive_enclosures/index.html

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?


On January 24, 2010 8:26:07 AM -0800 R.G. Keen k...@geofex.com wrote:

 In my case, I got 0.75TB drives
for $58 each. The cost per bit is bigger than buying 1TB or 1.5TB drives,
all right, but I can buy more of them, and that lets me put another drive
on for the next level of error correction data.


That's the point I was arguing against.  You did not respond to my
argument, and you don't have to now, but as long as you keep stating
this without correcting me I will keep responding.

The size of the drive has nothing to do with letting you put another
drive on, for more redundancy.  If you want more redundancy, you *have*
to buy more drives, whether big or small.  If you're implying that
because of the lower cost you can afford to buy the additional drive,
that also clearly incorrect as the cost per bit is more, so in fact
you spend more with the smaller drives PLUS the cost for the
additional redundancy.

Also, smaller drives require LESS redundancy for the same level of
availability, not more.  Of course, because drives are only available
in discrete sizes you may end up with the same raidz level (1,2 or 3)
anyway.

-frank
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?


On January 24, 2010 8:26:07 AM -0800 R.G. Keen k...@geofex.com wrote:

“Fewer/bigger versus more/smaller drives”: Tim and Frank have worked
this one over. I made the choice based on wanting to get a raidz3 setup,
for which more disks are needed than raidz or raidz2. This idea comes out
of the time-to-resilver versus time to failure line of reasoning.


Sorry I missed this part of your post before responding just a moment
ago.  If you want raidz3, you will spend more money on larger drives
if your data still fits into N smaller drives.  If you only have .75TB
of data, then of course it is a waste to get 1.5TB drives because you
still need 5 (1+3)+1 of them and you should definitely use the cheaper
.75TB drives.  But you'd do even better to use a triple mirror of the
smaller drives.

Once the size of your data exceeds the size of the smaller drive, and
you have to buy 2 of them just for the data part (not incl. the parity),
it's now more expensive to use the smaller drives.

In the above paragraph you haven't mentioned cost at all, but since
you did talk elsewhere about the cost of the smaller drives being cheaper,
I wanted to make it clear you are spending more money by using the smaller
drives.

-frank
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-24 Thread Tim Cook

On Sun, Jan 24, 2010 at 10:38 AM, Frank Cusack fcus...@fcusack.com wrote:

 On January 23, 2010 8:23:08 PM -0600 Tim Cook t...@cook.ms wrote:

 I bet you'll get the same performance out of 3x1.5TB drives you get out of
 6x500GB drives too.


 Yup.  And if that's the case, probably you want to go with the 3 drives
 because your operating costs (power consumption) will be less.


Nope.





   Are you really trying to argue people should never
 buy anything but the largest drives available?


 No.  Are you really so dense that you extrapolate my argument to an
 extremely broad catch-all?  There are other reasons besides cost that
 people might want to buy smaller drives.  And, e.g., if your data set
 isn't that large, don't spend money for space you don't need.

 The post that I was responding to claimed smaller drives *allowed* him
 to get to raidz3.  I challenged that as incorrect.  It's the larger
 drives that *require* raidz3 because resilver time is longer.  So far
 I've seen no argument to the contrary.  Just a side argument about
 cost which I happen to disagree with.  And a followup side argument
 about planning for redundancy which I also disagree with.


You're calling me dense and you think the sole purpose of him using raid-z3
is resilver time?  Hey guys, let's throw self-healing out the window when
using consumer drives because it's cheaper per GB to buy a larger drive
size.  You're trying to convince the OP not to use raid-z3 because you
either haven't read up, or find no benefit to some very real, and very
useful features he will see with it.



 Let's say you need 3TB of storage.  That's a lot for most home uses.
 The actual amount doesn't matter as the costs will scale.  So you
 buy 5 1.5TB drives.  4 (2+2) in a raidz2 plus a hot spare.  For the
 sake of this argument, let's say you've done the math and raidz2
 meets your redundancy requirement, based on time to resilver.  More
 likely, a home user has not done the math but that's besides the point.

 Now let's do it with .5GB drives.  A quick survey shows me they come
 in at about a 10% discount to the 1.5TB drives.  I'm being generous
 because I can't even find .5GB drives, but I see that 320GB drives
 are about 10% less.  If you want to get even cheaper, 250GB drives
 are about 50% less cost than 1.5TB drives (which by my argument, which
 you refute, makes them 3x more expensive but whatever).

 So with .5GB drives you need 6+3 drives -- because the smaller drives
 allows you to get to raidz2, plus a hot spare.  That's twice as many
 drives, however you are only paying 10% less per drive.  PLUS with this
 many drives you now need a pretty big chassis.  Plus your power costs
 are now quite a bit higher.

 Please put together a scenario for me where smaller drives cost less.



10%?  I'm not sure where you shop, but no.  The cheapest 500GB is $39.99.
 The cheapest 1.5TB is $97.99.

http://www.zipzoomfly.com/jsp/ProductDetail.jsp?ProductCode=10010737
http://www.newegg.com//Product/Product.aspx?Item=N82E16822148516

$359.91 for the 500GB drives.
$391.96 for the 1.5TB drives.


-- 
--Tim
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-24 Thread Will Murnane

On Sun, Jan 24, 2010 at 11:41, Erik Trimble erik.trim...@sun.com wrote:
 Rob Logan wrote:

 a 1U or 2U JBOD chassis for 2.5 drives,


 from http://supermicro.com/products/nfo/chassis_storage.cfm the E1
 (single) or E2 (dual) options have a SAS expander so
 http://supermicro.com/products/chassis/2U/?chs=216
 fits your build or build it your self with
 http://supermicro.com/products/accessories/mobilerack/CSE-M28E2.cf

 I'm aware of the Supermicro chassis, and, while they're nice, I'm after an
 external JBOD chassis, not a server chassis.
Depending on your needs, you may find adding a CSE-PTJBOD-CB1 card and
a CBL-0166L assembly (which functionally turn the chassis into a JBOD)
may suffice.  The total cost for such a system is about $1150 shipped
to me from Provantage.com, which is substantially less than any
big-name JBOD with similar qualities I can find.

Will
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-24 Thread Richard Elling

On Jan 24, 2010, at 8:26 AM, R.G. Keen wrote:
 
 “Disk drives cost $100”: yes, I fully agree, with minor exceptions. End of 
 marketing, which is where the cost per drive drops significantly, is 
 different from end of life – I hope!

http://en.wikipedia.org/wiki/End-of-life_(product)
Some vendors use EOSL to signify the end of service life, after which time the
product will no longer be serviced or warranted. The actual EOSL can change
since the product is no longer manufactured. For hardware, when the warranty
reserve is exhausted, EOSL may be forced.

For consumer disks, I think a model of 1 year of life + 3 years warranty is 
fairly consistent.  For enterprise disks, the enterprise market demands longer
warranty periods, like 5 years.  Warranty is a non-zero cost for the 
manufacturer
that is reflected in the price.
 -- richard

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-24 Thread Toby Thain



On 24-Jan-10, at 11:26 AM, R.G. Keen wrote:


...
I’ll just blather a bit. The most durable data backup medium humans  
have come up with was invented about 4000-6000 years ago. It’s  
fired cuniform tablets as used in the Middle East. Perhaps one  
could include stone carvings of Egyptian and/or Maya cultures in  
that. ...


The modern computer era has nothing that even comes close. ...


 And I can’t bet on a really archival data storage technology  
becoming available. It may not get there in my lifetime.



A better digital archival medium may already exist:
http://hardware.slashdot.org/story/09/11/13/019202/Synthetic-Stone- 
DVD-Claimed-To-Last-1000-Years


--Toby

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-24 Thread Joerg Schilling

Colin Raven co...@clearcutnetworks.com wrote:

  A better digital archival medium may already exist:
  http://hardware.slashdot.org/story/09/11/13/019202/Synthetic-Stone-
  DVD-Claimed-To-Last-1000-Years


 That would be nice - but - I have to wonder how they would test it in order
 to justify the actual lifespan claim. Seems like the first real aging test
 would be down the road aways. Just as well it's a start-up I guess.
 Mezzanine funding round...to come...

100 years apply to the DVD media that was made in 1998 by Pioneer and TDK.
The cost of a single media these days was ~ 70 Euro. I would guess that current
media will not last as long as media from 1998.

BluRay BD-R media is not based on organic dye but on metall-nitrides. I would 
guess that BD-R for this reason lasts longer and is not affected by UV rays.

The article mentined above does not contain enough information to be able to 
judge on it.

Jörg

-- 
 EMail:jo...@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
   j...@cs.tu-berlin.de(uni)  
   joerg.schill...@fokus.fraunhofer.de (work) Blog: 
http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/private/ ftp://ftp.berlios.de/pub/schily
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-24 Thread R.G. Keen

On January 24, 2010 Frank Cusack wrote:
That's the point I was arguing against. 
Yes, that's correct.

You did not respond to my argument, and you don't have to now, 
Thanks for the permission. I'll need that someday.

but as long as you keep stating this without correcting me I will keep 
responding.
As is your perfect right. You have my permission to say anything you like; I do 
like a guy who's persistent. But if you'll re-read what I wrote, I think you 
may have left out my implicit phrase ... for me... in describing my problem 
and my solution. I would never presume to correct you. Your situation is almost 
certainly different from mine. I do however believe that situations like the 
one we are describing must be described in context, because when we start 
discussing failure rates and economics as well as different objectives, the 
scoring polynomials get complicated fast.

The size of the drive has nothing to do with letting you put another drive on, 
for 
more redundancy. 
That is correct. I can obviously buy more drives no matter how big they are. As 
I used to tell girls in bars, I'm not really this tall, I'm just sitting on my 
wallet. It was remarkably effective. 8-)  Just buy more, bigger drives is a 
good solution, if the sheer number of bits or lowest cost per bit is what 
you're after.

However, I may not have been clear about my point. More, smaller drives, within 
limits may be better in some circumstances, depending on how you look at the 
problem. I thought that I was clear about the within 
limits/practicality/reason approach, in my rambling. If not, let me say it. No 
generality is worth a d..., including this one. There is only fitness for 
context. Do what's practical within your context. And have a good time at it. 
But contexts are rarely as simple as get more bits or get the densest 
drives when you have multiple objectives.

As I obviously muffed explaining, more and smaller drives, for not too much 
cost penalty (where we all get to define how much smaller and how much more 
cost penalty in our own personal contexts) leads to a lower recover/resilver 
time per failed disk than grabbing the densest, most bit stuffed drives; this 
is because to a first order, the time to get bits onto a new disk is 
proportional to the number of bits. This changes in steps as the interfaces get 
faster, but is likely to not keep up with the sheer number of bits. I know this 
because I read it on the internet and that makes it true, right? 8-) I've got 
that reference here somewhere if it's pertinent.

Obviously, taken to extreme, a zillion one-bit drives is not a cost effective 
solution. We're all here at least partly because a single zettabyte drive has 
some issues as well. I suspect that on this continuum, there is not a single 
answer of X drives of Y size is the best answer for all situations. Maybe there 
are two answers, perhaps even three.

In my own, personal, dim-witted, benighted context of evaluation, for which I 
reserve the right to be wrong, I judged that for me, at this time, in the 
technological context I happen to be in right now, it's better to get a few 
more drives to get more increments of physical failure possibility if that also 
includes more redundancy mechanisms (i.e. raidz3) so that I have a better 
chance of correcting silent bit errors before a second drive failure makes the 
data lost. In that limited, miniscule, probably useless context where the I/O 
rates onto and off the disk are the same for all the drives being considered, I 
judge that cutting the time to re-silver a replacement disk may be more 
desirable than getting the absolute most disks. It's a different viewpoint, 
albeit probably limited and shortsighted as I've stated. But I thought it might 
be helpful to someone else, if only as a starter idea for thinking about disk 
drives on a basis other than bits/dollar. Perhaps the most bits p
 er dollar is, in fact, the best strategy; however, it ought to be checked out 
if there are other ways to looking at it, depending on what you're trying to do.

 smaller drives require LESS redundancy for the same level of availability
Maybe that's the problem. I'm not after availability. Back in the bad old days 
when I sold my soul to a giant corporation every day, we distinguished between 
reliability, availability, and serviceability.  I'm after serviceability. 
Reliability and availability are close, but not the same concepts.

Anyway, thanks for hanging in there and helping me figure it out. I guess I 
just had this simple minded idea that all situations of evaluating how many 
drives of what density might not reduce to only the lowest cost per bit at any 
given time. Silly, right? 8-)

R.G.
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-24 Thread Daniel Carosone

Another issue with all this arithmetic: one needs to factor in the
cost of additional spare disks (what were you going to resilver onto?).

I look at it like this: you purchase the same number of total disks
(active + hot spare + cold spare), and raidz2 vs raidz3 simply moves a
disk from one of the spare columns to the active column. Raidz3 gives
you longer to find (potentially even purchase, at future cheaper
prices) the replacement disk, which might simply be a replacement cold
spare. 

On Sun, Jan 24, 2010 at 12:20:37PM -0500, Frank Cusack wrote:
 But you'd do even better to use a triple mirror of the
 smaller drives.

By R.G's now well-stated and clear objectives and criteria for
better, no.  He'd need at least a 4-way mirror, to survive 3
faults.  Sorry to nit-pick your arithmetic again :)

Assuming 4 active disks total (for capital cost equivalence), when it
comes to other criteria, like random-IOPS, most of use would prefer
the mirror, of those two configs.  If those criteria are not as
important to you, there may still be reasons to prefer raidz3, perhaps
because different data patterns are written to each disk, protecting
you against some potential data-sensitive deficiency in the on-disk
error recovery. 

If you want any more than 3 faults, your only choice is mirrors (for
now).   By - or even well before - that stage, you should be looking
at off-site replication.

--
Dan.

pgpA7fu5NcTfV.pgp
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-24 Thread Bob Friesenhahn


On Sun, 24 Jan 2010, Frank Middleton wrote:


You seem to have it in for Seagate :-). Newegg by default displays reviews
worst to best. The review statistics as of 23 Jan 2010) were:

ST31500341AS (older, 7200RPM 1.5GB drive)

Excellent  911 - 49%
Good233 - 12%
Average 113 - 6%
Poor   123 - 6%
Very Poor 514 - 27%


It is always wise to consider that people with good experiences have 
little incentive to come back and give a rating whereas people with 
bad experiences have considerable incentive to do so.  The text of the 
comments is much more useful than raw percentages.


Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,http://www.GraphicsMagick.org/
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-24 Thread Richard Elling

On Jan 24, 2010, at 8:26 PM, Frank Middleton wrote:

What an entertaining discussion! Hope the following adds to the
entertainment value :).

Any comments on this Dec. 2005 study on disk failure and error rates?
http://research.microsoft.com/apps/pubs/default.aspx?id=64599

Seagate says their 1.5TB consumer grade drives are good for 24*365
operation. http://labs.google.com/papers/disk_failures.pdf implies yes.
This paper is quite interesting. Power cycles - bad. High temps - not
so bad...

The specs say an annualized failure rate of 0.34% and mean time between
failures of 750,000 hours. 8760/750,000 = 1.17%. Hmmm. So around one
disk in a hundred will fail each year? What does that mean to a system with
a simple mirror if one disk in 20 will fail in 5 years?

Unfortunately, this is marketeering and you need to look at the footnotes
to get the real story.
http://blogs.sun.com/relling/entry/awesome_disk_afr_or_is

What is the MTTDL of a mirrored pair of consumer grade 1.5TB drives,
or the probability of a single data loss (say) during a 5 year period,
perhaps compared to the probability (say) of winning the lottery :-),
or being hit by a 20 ton meteor, assuming at least one device failure?

MTTDL using model[2] for a Seagate ST31500341AS and 7x24x365
operation:
MTBF = 700,000 hours
UER = 1 error per 1e14 bits read, max
1.5 TB = 2,930,277,168 512-byte sectors
Precon_fail = 2,930,277,168 * 512 bytes/sector * 8 bits/byte / 1e-14 =
0.12
MTTDL = 700,000 / (2 * 0.12) = 2,916,666 hours

This is not that great, really. To bring it back to something a bit more
understandable, it is an annualized data loss rate of 0.3 %.

references for above:
http://www.seagate.com/staticfiles/support/disc/manuals/desktop/Barracuda%207200.11/100507013e.pdf

The OP originally asked Best 1.5TB drives for consumer RAID?. Despite
the entertainment value of the comments, it isn't clear that this has been
answered. I suspect the OP was expecting a discussion of WD vs. Seagate
vs. Hitachi, etc., but the discussion didn't go that way, perhaps because
they are equally good (or bad) based on the TLER discussion? Has anyone
actually experienced an extended timeout from one of these drives (from
any manufacturer) causing a problem?

Extended timeouts lead to manual intervention, not a change in the
probability of data loss. In other words, they affect the MTTR, not
the reliability. For a 7x24x365 deployments, MTTR is a concern because
it impacts availability. For home use, perhaps not so much.
-- richard

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread R.G. Keen

Interesting question. 

The answer I came to, perhaps through lack of information and experience, is 
that there isn't a best 1.5tb drive. I decided that 1.5tb is too big, and that 
it's better to use more and smaller devices so I could get to raidz3.

The reasoning came after reading the case for triple-parity raid. The curves 
showing time to failure versus time to resilver a single lost drive. Time to 
failure will remain constant-ish, while time to resilver will increase as the 
number of bits inside a single drive increases, largely because the 
input/output bandwidth is going to increase only very slowly. The bigger the 
number of bits in a single drive compared to the time to write a new, full disk 
worth of bits, the bigger the window for a second-drive failure. Hence, the 
third parity version is desirable. 

In general, more drives of smaller capacity within reason for a vdev, the less 
exposure to a double fault. 

This led me to look at sub-terabyte drives, and that's how I accidentally found 
those 0.75GB raid-rated drives, although the raid rated wasn't what I was 
looking for. I was after the best cost/bit in a six-drive batch with a top cost 
limit. 

After reading through the best practices stuff, I clumsily decided that a 
six- or seven-drive raidz3 would be a good idea. And I have a natural leaning 
to stay !OFF! the leading edge of technology where keeping data reliable is 
involved. It's a personal quirk I learned by getting several scars to remind 
me. 

How's that for a mismash of misunderstanding?   8-)
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

pI just took a look at customer feedback on this drive here. 36% rate with 
one star, which I would consider alarming. Take a look here, ordered from 
lowest rating to highest rating. Note the recency of the comments and the 
descriptions:/p

a 
href=http://www.newegg.com/Product/ProductReview.aspx?Item=22-148-412SortField=3SummaryType=0Pagesize=10SelectedRating=-1PurchaseMark=VideoOnlyMark=FalseVendorMark=Page=1Keywords=%28keywords%29;Seagate
 Barracuda LP ST31500541AS 1.5TB 5900 RPM/a

pIs this the model you mean? If so, I might look at some other alternative 
possibilities./p

pSo, we have apparently problematic newest revision WD Green 'EADS' and 
'EARS' models, and an apparently problematic Seagate model described here./p

pThat leaves Hitachi and Samsung./p

pI had past 'experiences' with post IBM 'deathstar' Hitachi drives, so I 
think for now I shall be looking into the Samsungs, as from the customer 
reviews it seems these could be the most reliable consumer-priced high-capacity 
drives available right now./p

pIt does seem that it is proving to be a big challenge for the drive 
manufacturers to produce reliable high-capacity consumer-priced drives. Maybe 
this is Samsung's opportunity to prove how good they are?/p

a 
href=http://www.newegg.com/Product/Product.aspx?Item=N82E16822152175Tpk=HD154UI;Samsung
 1.5TB HD154UI 3-platter drive/a
a 
href=http://www.newegg.com/Product/Product.aspx?Item=N82E16822152202Tpk=HD203WI;Samsung
 2TB HD203WI 4-platter drive/a
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?


On Sat, 23 Jan 2010, R.G. Keen wrote:

The reasoning came after reading the case for triple-parity raid. 
The curves showing time to failure versus time to resilver a single 
lost drive. Time to failure will remain constant-ish, while time to 
resilver will increase as the number of bits inside a single drive 
increases, largely because the input/output bandwidth is going to 
increase only very slowly. The bigger the number of bits in a single 
drive compared to the time to write a new, full disk worth of bits, 
the bigger the window for a second-drive failure. Hence, the third 
parity version is desirable.


Resilver time is definitely important criteria.  Besides the number of 
raw bits to transfer from the drive, you will also find that today's 
super-capacity SATA drives rotate more slowly, which increases access 
times.  Since resilver is done in (roughly) the order that data was 
written, access time will be important to resilver times.  A pool 
which has aged due to many snapshots, file updates, and file 
deletions, will require more seeks.  The smaller drives are more 
responsive so their improved access time will help reduce resilver 
times.


In other words, I think that you are making a wise choice. :-)

Bob
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

In general I agree completely with what you are saying. Making reliable large 
capacity drives does appear to have become very difficult for the drive 
manufacturers, judging by the many sad comments from drive buyers listed on 
popular, highly-trafficked sales outlets' websites, like newegg.

And I think your 750GB choice should be a good one. I'm currently using 750GB 
drives (WD7500AAKS) and they have worked flawlessly over the last 2 years. But 
knowing that drives don't last forever, it's time I looked for some new ones, 
assuming they can be reasonably assumed to be reliable from customer ratings 
and reports.

If there's one manufacturer that *may* possibly have proved the exception, it 
might be Samsung with their 1.5TB and 2TB drives -- see my post just a little 
further up.

And using triple parity RAID-Z3 does seem a good idea now when using these 
higher capacity drives. Or perhaps RAID-Z2 with a hot spare? I don't know which 
is better -- I guess RAID-Z3 is better, AND having a spare available ready to 
replace a failed drive when it happens. But I think I read that unused drive 
bearings seize up if unused so I don't know. Any comments?

For resilvering to be required, I presume this will occur mostly in the event 
of a mechanical failure. Soft failures like bad sectors will presumably not 
require resilvering of the whole drive to occur, as these types of error are 
probably easily fixable by re-writing the bad sector(s) elsewhere using 
available parity data in redundant arrays. So in this case larger capacities 
and resilvering time shouldn't become an issue, right?

And there's one big item of huge importance here, which is often overlooked by 
people, and that is the fact that one should always have a reasonably current 
backup available. Home RAID users often pay out the money for a high-capacity 
NAS and then think they're safe from failure, but a backup is still required to 
guard against loss.

I do have a separate Solaris / ZFS machine dedicated to backups, but I do admit 
to not using it enough -- something I should improve. It contains a backup but 
an old one. Part of the reason for that is that to save money, I filled it with 
old drives of varying capacity in a *non-redundant* config to maximise 
available space from smaller drives mixed with larger drives. Being 
non-redundant, I shouldn't depend on its integrity, as there is a high 
likelihood of it containing multiple latent errors (bit rot).

What might be a good idea for a backup box, is to use a large case to house all 
your old drives using multiple matched drive-capacity redundant vdevs. This 
way, each time you upgrade, you can still make use of your old drives in your 
backup machine, without disturbing the backup pool - i.e. simply adding a new 
vdev each time...
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread David Magda


On Jan 23, 2010, at 12:04, Simon Breden wrote:

And I think your 750GB choice should be a good one. I'm currently  
using 750GB drives (WD7500AAKS) and they have worked flawlessly over  
the last 2 years. But knowing that drives don't last forever, it's  
time I looked for some new ones, assuming they can be reasonably  
assumed to be reliable from customer ratings and reports.


If there's one manufacturer that *may* possibly have proved the  
exception, it might be Samsung with their 1.5TB and 2TB drives --  
see my post just a little further up.


Have your storage needs expanded such that you've outgrown your  
current capacity? It may seem counter-intuitive, but is it worth  
considering replacing your current 750 GB drives with newer 750 GB  
drives, instead of going to a larger size?


Would simply buying new drives be sufficient to get a new warranty,  
and presumably a device that has less wear on it? More is not always  
better (though it is more :).


For resilvering to be required, I presume this will occur mostly in  
the event of a mechanical failure. Soft failures like bad sectors  
will presumably not require resilvering of the whole drive to occur,  
as these types of error are probably easily fixable by re-writing  
the bad sector(s) elsewhere using available parity data in redundant  
arrays. So in this case larger capacities and resilvering time  
shouldn't become an issue, right?


Correct. Though it's recommended to run a 'scrub' on a regular  
(weekly?) basis to make sure data corruption / bit flipping is caught  
early. This will take some time and eat I/O, but can be done during  
low traffic times (overnight?). Scrubbing (like resilvering) is only  
done over used blocks, and not over the entire drive(s).


And there's one big item of huge importance here, which is often  
overlooked by people, and that is the fact that one should always  
have a reasonably current backup available. Home RAID users often  
pay out the money for a high-capacity NAS and then think they're  
safe from failure, but a backup is still required to guard against  
loss.


Depends on what the NAS is used for. It may be backup volume for the  
desktops / laptops of the house. In which case it's not /that/  
essential for a backup of the backup to be done--though copying the  
data to an external drive regularly, and taking that offsite (work)  
would be useful in the case of fire or burglary.


Of course if the NAS is the 'primary' data store for any data, and  
you're not replicating that data anywhere, you're tempting fate. There  
are two types of computer users: those have experienced catastrophic  
data failure, and those that will.


I use OS X at home and have a FireWire drive for Time Machine, but I  
also purchased a FW dock and two stand-alone hard drives in which I  
use SuperDuper! to clone my boot volume to every Sunday. Then on  
Monday I take the drive (A) to work, and bring back the one I have  
there (Disk B). The syncing takes about 25 minutes each week with  
minimal effort (plug-in drive, launch SD!, press Copy).


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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?


On January 23, 2010 8:04:50 AM -0800 R.G. Keen k...@geofex.com wrote:

The answer I came to, perhaps through lack of information and experience,
is that there isn't a best 1.5tb drive. I decided that 1.5tb is too big,
and that it's better to use more and smaller devices so I could get to
raidz3.


Please explain.  I don't understand how smaller devices gets you to
raidz3.  With smaller devices, you probably have less need for raidz3
as you have more redundancy?  It's the larger drives that forces you
to add more parity.

-frank
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

Reading through your post brought back many memories of how I used to manage my 
data.

I also found SuperDuper and Carbon Copy Cloner great for making a duplicate of 
my Mac's boot drive, which also contained my data.

After juggling around with cloning boot/data drives and using non-redundant 
Time Machine backups etc, plus some manual copies here and there, I said 'there 
must be a better way' and so the long search ended up with the idea of having 
fairly 'dumb' boot drives containing OS and apps for each desktop PC and moving 
the data itself onto a redundant RAID NAS using ZFS. I won't bore you with the 
details any more -- see the link below if it's interesting. BTW, I still use 
SuperDuper for cloning my boot drive and it IS terrific.

Regardless of where the data is, one still needs to do backups, like you say. 
Indeed, I know all about scrub and do that regularly and that is a great tool 
to guard against silent failure aka bit rot.

Once your data is centralised, making data backups becomes easier, although 
other problems like the human factor still come into play :)

If I left my backup system switched on 24/7 it would in theory be fairly easy 
to (1) automate NAS snapshots and then (2) automate zfs sends of the 
incremental differences between snapshots, but I don't want to spend the money 
on electricity for that.

And when buying drives every few years, I always try to take advantage of 
Moore's law.

Cheers,
Simon

http://breden.org.uk/2008/03/02/a-home-fileserver-using-zfs/
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?


On Sat, 23 Jan 2010, Simon Breden wrote:


pI just took a look at customer feedback on this drive here. 36% rate with one 
star, which I would consider alarming. Take a look here, ordered from lowest rating to 
highest rating. Note the recency of the comments and the descriptions:/p

a 
href=http://www.newegg.com/Product/ProductReview.aspx?Item=22-148-412SortField=3SummaryType=0Pagesize=10SelectedRating=-1PurchaseMark=VideoOnlyMark=FalseVendorMark=Page=1Keywords=%28keywords%29;Seagate
 Barracuda LP ST31500541AS 1.5TB 5900 RPM/a

pIs this the model you mean? If so, I might look at some other alternative 
possibilities./p


This looks like a really good drive for use with zfs.  Be sure to use 
a mirror configuration and keep in mind that zfs supports an arbitrary 
number of mirrors so that you can run six or ten of these drives in 
parallel so that there are enough working drives remaining to keep up 
with RMAed units.


Be sure to mark any failed drive using a sledgehammer so that you 
don't accidentally use it again by mistake.


Bob
--
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bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,http://www.GraphicsMagick.org/
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread A. Krijgsman


Just to jump in.

Did you guys ever consider to shortstroke a larger sata disk?
I'm not familiar with this, but read a lot about it;

Since the drive cache gets larger on the bigger drives.
Bringing back a disk to roughly 25% of its capicity would give better cache 
ratio and less seektime.


So 2TB would become 500GB, but better then a normal 500GB SATA.
( Or in your case, swing it down to 750Gb )

Regards,
Armand




- Original Message - 
From: Simon Breden sbre...@gmail.com

To: zfs-discuss@opensolaris.org
Sent: Saturday, January 23, 2010 7:53 PM
Subject: Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?



Hi Bob,

Why do you consider that model a good drive?

Why do you like to use mirrors instead of something like RAID-Z2 / 
RAID-Z3?


And how many drives do you (recommend to) use within each mirror vdev?

Cheers,
Simon

http://breden.org.uk/2008/03/02/a-home-fileserver-using-zfs/
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?


On Sat, 23 Jan 2010, Simon Breden wrote:


Why do you consider that model a good drive?


This is a good model of drive to test zfs's redundancy/resiliency 
support.  It is surely recommended for anyone who does not have the 
resources to simulate drive failure.



Why do you like to use mirrors instead of something like RAID-Z2 / RAID-Z3?


Because raidz3 only supports tripple redundancy but mirrors can 
support much more.



And how many drives do you (recommend to) use within each mirror vdev?


Ten for this model of drive.

Bob
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bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,http://www.GraphicsMagick.org/
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?


On Sat, 23 Jan 2010, A. Krijgsman wrote:


Just to jump in.

Did you guys ever consider to shortstroke a larger sata disk?
I'm not familiar with this, but read a lot about it;

Since the drive cache gets larger on the bigger drives.
Bringing back a disk to roughly 25% of its capicity would give better cache 
ratio and less seektime.


Consider that a drive cache may be 16MB but the ZFS ARC cache can span 
up to 128GB of RAM in current servers, or much larger if SSDs are used 
to add a L2ARC.  It seems to me that once the drive cache is large 
enough to contain a full drive track, that it is big enough.  Perhaps 
a large drive cache may help with write performance.  GB beats MB any 
day of the week.



So 2TB would become 500GB, but better then a normal 500GB SATA.
( Or in your case, swing it down to 750Gb )


Or you could buy a smaller enterprise drive which is short-stroked by 
design.


Bob
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GraphicsMagick Maintainer,http://www.GraphicsMagick.org/
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread Richard Elling

On Jan 23, 2010, at 12:12 PM, Bob Friesenhahn wrote:

 On Sat, 23 Jan 2010, A. Krijgsman wrote:
 
 Just to jump in.
 
 Did you guys ever consider to shortstroke a larger sata disk?
 I'm not familiar with this, but read a lot about it;
 
 Since the drive cache gets larger on the bigger drives.
 Bringing back a disk to roughly 25% of its capicity would give better cache 
 ratio and less seektime.
 
 Consider that a drive cache may be 16MB but the ZFS ARC cache can span up to 
 128GB of RAM in current servers, or much larger if SSDs are used to add a 
 L2ARC.  

Wimpy servers! To rewrite for 2010,
Consider that a drive cache may be 16MB but the ZFS ARC cache can span 
up to
4 TB of RAM in current servers, or much larger if SSDs are used to add 
a L2ARC.  

:-)
 -- richard

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread Richard Elling

On Jan 23, 2010, at 8:04 AM, R.G. Keen wrote:
 Interesting question. 
 
 The answer I came to, perhaps through lack of information and experience, is 
 that there isn't a best 1.5tb drive. I decided that 1.5tb is too big, and 
 that it's better to use more and smaller devices so I could get to raidz3.

My theory is that drives cost $100. When the price is  $100, the drive is
manufactured.  When the price is  $100, the drive is EOL and the manufacturer
is flushing the inventory. Recently, 1.5 TB drives went below $100.

So, if you consider avoiding the leading edge by buying EOL product,
then it might not sound like such a good idea :-)
 -- richard

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

How does a previously highly rated drive that costed $100 suddenly become 
substandard when it costs $100 ?

I can think of possible reasons, but they might not be printable here ;-)

Cheers,
Simon

http://breden.org.uk/2008/03/02/a-home-fileserver-using-zfs/
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread Daniel Carosone

On Sat, Jan 23, 2010 at 12:30:01PM -0800, Simon Breden wrote:
 And regarding mirror vdevs etc, I can see the usefulness of being
 able to build a mirror vdev of multiple drives for cases where you
 have really critical data -- e.g. a single 4-drive mirror vdev. I
 suppose regular backups can help with critical data too. 

Multi-way mirrors have lots of uses:
 - seek independence, for heavily read-biased loads (writes tend to
   kill this quickly by forcing all drives to seek together).
 - faster resilver times with less impact to production load (resilver
   reads are a particular case of the above)
 - capacity upgrades without losing redundancy in the process (note
   this is inherently n+1, proof by induction for arbitrary mirrors)
 - lots of variations of the attach another mirror, sync and detach
   workflow that zpool clone was created to support, whether for
   backup or reporting or remote replication or test systems or ..
 - burning in or qualifying new drives, to work out early failures
   before putting them in service (easy way to amplify a test workload
   by say 10x). Watch for slow units, as well as bad data/scrub
   fails.  Just as good for amplifying test workload for controllers
   and other components.

and.. um.. 

 - testing dedup (make a n-way mirror out of n zvols on the same
   dedup'ed pool; comstar optional :)

More seriously, though, it's for some of these scenarios that the zfs
limitation of not being able to layer pool types (easily) is most
irritating (raidz of mirrors, mirror of raidz).  Again, that's in part
because of practices developed previously; zfs may eventually offer
even better solutions, but not yet.

--
Dan.

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread Daniel Carosone

On Sat, Jan 23, 2010 at 09:04:31AM -0800, Simon Breden wrote:
 For resilvering to be required, I presume this will occur mostly in
 the event of a mechanical failure. Soft failures like bad sectors
 will presumably not require resilvering of the whole drive to occur,
 as these types of error are probably easily fixable by re-writing
 the bad sector(s) elsewhere using available parity data in redundant
 arrays. So in this case larger capacities and resilvering time
 shouldn't become an issue, right? 

Correct.  However, consider that it's actually the *heads* that
contribute most to errors accumulating; over time they lose the
ability to read with the same sensitivity, for example.  Of course
this shows up first in some areas of the platter that already had
slightly more marginal surface quality. 

This is why smart and similar systems consider both the absolute
number of bad sectors, as well as the rate of discovery, as predictors
of device failure.

 What might be a good idea for a backup box, is to use a large case
 to house all your old drives using multiple matched drive-capacity
 redundant vdevs. This way, each time you upgrade, you can still make
 use of your old drives in your backup machine, without disturbing
 the backup pool - i.e. simply adding a new vdev each time... 

This is basically my scheme at home - current generation drives are in
service, the previous generation go in the backup pool, and the set
before that become backup tapes.  Every so often the same thing
happens with the servers/chassis/controller/housing stuff, too.
It's coming up to time for exactly one of those changeovers now.

I always have a bunch of junk data in the main pool that really
isn't worth backing up, which helps deal with the size difference.
There's no need to constantly add vdevs to the backup pool, just do
replacement upgrades the same as you did with your primary pool. 

I, too, will admit to not being as diligent at putting the scheme into
regular practice as theory would demand.  I may also relocate the backup
pool at a neigbours house soon (or, really, trade backup pool space
with him).

--
Dan.

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread Tim Cook

On Sat, Jan 23, 2010 at 11:41 AM, Frank Cusack fcus...@fcusack.com wrote:

 On January 23, 2010 8:04:50 AM -0800 R.G. Keen k...@geofex.com wrote:

 The answer I came to, perhaps through lack of information and experience,
 is that there isn't a best 1.5tb drive. I decided that 1.5tb is too big,
 and that it's better to use more and smaller devices so I could get to
 raidz3.


 Please explain.  I don't understand how smaller devices gets you to
 raidz3.  With smaller devices, you probably have less need for raidz3
 as you have more redundancy?  It's the larger drives that forces you
 to add more parity.

 -frank



Smaller devices get you to raid-z3 because they cost less money.  Therefore,
you can afford to buy more of them.

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?


On January 23, 2010 5:17:16 PM -0600 Tim Cook t...@cook.ms wrote:

Smaller devices get you to raid-z3 because they cost less money.
Therefore, you can afford to buy more of them.


I sure hope you aren't ever buying for my company! :) :)

Smaller devices cost more $/GB; ie they are more expensive.

-frank
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?


On January 23, 2010 1:20:13 PM -0800 Richard Elling

My theory is that drives cost $100.


Obviously you're not talking about Sun drives. :)

-frank
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

Hey Dan,

Thanks for the reply.

Yes, I'd forgotten that it's often the heads that degrade -- something like 
lubricant buildup, IIRC.
As well as SMART data, which I must admit to never looking at, presumably scrub 
errors are also a good indication of looming trouble due to head problems etc? 
As I've seen zero read/write/checksum errors after regular scrubs over 2 years, 
hopefully this is a reasonably good sign of r/w head health.

Good to see you're already using a backup solution I have envisaged using. It 
seems to make sense: making use of old kit for backups to help preserve ROI on 
drive purchases -- even, no especially, for home users.

Cheers,
Simon

http://breden.org.uk/2008/03/02/a-home-fileserver-using-zfs/
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread Tim Cook

On Sat, Jan 23, 2010 at 5:39 PM, Frank Cusack fcus...@fcusack.com wrote:

 On January 23, 2010 5:17:16 PM -0600 Tim Cook t...@cook.ms wrote:

 Smaller devices get you to raid-z3 because they cost less money.
 Therefore, you can afford to buy more of them.


 I sure hope you aren't ever buying for my company! :) :)

 Smaller devices cost more $/GB; ie they are more expensive.


First off, smaller devices don't necessarily cost more $/GB, but that's not
really the point.  For instance, the cheapest drive per GB is a 1.5TB drive
today.  The third cheapest is a 1TB drive.  2TB drives aren't even in the
top ten.  Regardless that's a great theory when you have an unlimited
budget.  When you've got a home system and X amount of dollars to spend,
$/GB means absolutely nothing when you need a certain number of drives to
have the redundancy you require.

-- 
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread Richard Elling

On Jan 23, 2010, at 3:47 PM, Frank Cusack wrote:

 On January 23, 2010 1:20:13 PM -0800 Richard Elling
 My theory is that drives cost $100.
 
 Obviously you're not talking about Sun drives. :)

Don't confuse cost with price :-)
 -- richard

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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread Daniel Carosone

On Sat, Jan 23, 2010 at 06:39:25PM -0500, Frank Cusack wrote:
 On January 23, 2010 5:17:16 PM -0600 Tim Cook t...@cook.ms wrote:
 Smaller devices get you to raid-z3 because they cost less money.
 Therefore, you can afford to buy more of them.

 I sure hope you aren't ever buying for my company! :) :)

 Smaller devices cost more $/GB; ie they are more expensive.

Usually, other than the very largest (most recent) drives, that are
still at a premium price.  

However, it all depends on your budget considerations.  Budget applies
not only to currency.  You may be more constrained by available
controller ports, motherboard slots, case drive bays, noise, power,
heat or other factors.

Even if it still comes back to currency units, adding more ports or
drive bays can easily outweigh the cost of the drives to go on/in
them, especially in the consumer market. There's usually a big step
where just one more drive means a totally different solution.

If you're targetting total available space, small drives really do
cost more for the same space, when all these factors are counted.
That's what sells the bigger drives, despite the premium.

The other constraint is redundancy - I need N drives (raidz3 in the
OP's case), the smaller size is big enough and maybe the only way to
also be cheap enough.

--
Dan.



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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread Mirko

 pI just took a look at customer feedback on this
 drive here. 36% rate with one star, which I would
 consider alarming. Take a look here, ordered from
 lowest rating to highest rating. Note the recency of
 the comments and the descriptions:/p
 

Every people vote in different way for the same things.
A lot of 1 star are about DOA. Maybe Neweggs have a bad batch (happens 
sometimes)
The Bad news propagate much faster that the good ones. A angry user is more 
probable to post a bad review that a happy user.
120 review are a tiny sample to make a decision.
look in the other way 50% is 4-5 stars, 1/2 is very happy. 
I've said that every brand have problem at moment.
At 1.5TB there's few choice.
For me the RMA service have a important role, because I expect to use it. I 
don't expect to see the five HDDs running flawless for 3 years.
Samsung have no direct RMA service in my country, so the tournaround is a shoot 
in the dark, few weeks, maybe a month.   

Pick a rock solid product is more a matter of luck.
I've a Deskstar DTLA da 13GB, runnings strong after nealy 11 years or so ! 
maybe it's the last ones alive. Reading all over internet it should be dead 12 
years ago.
If the failure rate was 36% Seagate was toast.
The Barracuda LP can't be the right driver for everyone, but if you look at 
1.5TB cheap consumer driver, that run coolquiet it deserve strong cosideration.
It's better on the paper that the WD green, (stardard sector, no start/stop 
cycle after 8 sec of inactivity), Hitachi have no 1.5TB at the moment. samsung 
have a new recent model, the 7200.11 is a old product on 4 platters.
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?

2010-01-23 Thread Mirko

I just took a look at customer feedback on this  drive here. 36% rate with 
one star, which I would  consider alarming. Take a look here, ordered from 
lowest rating to highest rating. Note the recency of the comments and the 
descriptions:

Every people vote in different way for the same things. A lot of 1 star are 
about DOA. Maybe Neweggs have a bad batch (happens sometimes) The Bad news 
propagate much faster that the good ones. A angry user is more probable to post 
a bad review that a happy user. 120 review are a tiny sample to make a 
decision. look in the other way 50% is 4-5 stars, 1/2 is very happy. I've said 
that every brand have problem at moment. At 1.5TB there's few choice. For me 
the RMA service have a important role, because I expect to use it. I don't 
expect to see the five HDDs running flawless for 3 years. Samsung have no 
direct RMA service in my country, so the tournaround is a shoot in the dark, 
few weeks, maybe a month. Pick a rock solid product is more a matter of luck. 
I've a 13GB Deskstar DTLA, runnings strong after nealy 11 years or so ! maybe 
it's the last ones alive. Reading all over internet it should be dead 12 years 
ago. If the failure rate was 36% Seagate was toast. The Barracuda LP ca
 n't be the right driver for everyone, but if you look at 1.5TB cheap consumer 
driver, that run coolquiet it deserve strong cosideration. It's better on the 
paper that the WD green, (stardard sector, no start/stop cycle after 8 sec of 
inactivity), Hitachi have no 1.5TB at the moment. samsung have a new recent 
model, the 7200.11 is a old product on 4 platters.
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Re: [zfs-discuss] Best 1.5TB drives for consumer RAID?