On Mon, Oct 15, 2012 at 5:02 PM, Richard Elling
richard.ell...@richardelling.com wrote:
There is some interesting research that shows how scrubs for RAID-5
systems can
contaminate otherwise good data. The reason is that if a RAID-5 parity
mismatch
occurs, how do you know where the data
On Mon, Oct 15, 2012 at 6:21 PM, Jason Matthews ja...@broken.net wrote:
From: heinrich.vanr...@gmail.com [mailto:heinrich.vanr...@gmail.com]
My point is most high end storage units has some form of data
verification process that is active all the time.
As does ZFS. The blocks are
much rather bank on the controller.
my few cents on scrubs.
Thanks
From: Jim Klimov
Sent: October 13, 2012 9:02
To: Discussion list for OpenIndiana
Subject: Re: [OpenIndiana-discuss] Zfs stability Scrubs
2012-10-13 7:26, Michael Stapleton wrote:
The VAST
2012-10-16 3:57, Heinrich van Riel wrote:
Understood, if full backups are executed weekly/monthly no scrub is
required.
I'd argue that this is not a completely true statement.
It might hold for raidzN backing storage with single-copy blocks,
but if mirrors and/or two or three copies are
Thank you all for the good answers!
So if i put it all together :
1. ZFS is, in mirror and RAID configs, the best currently available option for
reliable data
2. Without scrubs data is checked on every read for integrity
3. Unread data will not be checked for integrity
4. Scrubs will solve point
10. If SUN had listen to the engineers instead of financials it now would have
been marketleader in the server market ;-(
Op 13 okt. 2012 om 09:56 heeft Roel_D openindi...@out-side.nl het volgende
geschreven:
Thank you all for the good answers!
So if i put it all together :
1. ZFS is,
2012-10-13 2:06, Jan Owoc wrote:
All scrubbing does is put stress on drives and verify that data can
still be read from them. If a hard drive ever fails on you and you
need to replace it (how often does that happen?), then you know hey,
just last week all the other hard drives were able to read
A few more comments:
2012-10-13 11:56, Roel_D wrote:
Thank you all for the good answers!
So if i put it all together :
1. ZFS is, in mirror and RAID configs, the best currently available option for
reliable data
Yes, though even it is not replacement for backups, because
data loss can be
2012-10-13 7:26, Michael Stapleton wrote:
The VAST majority of data centers are not storing data in storage that
does checksums to verify data, that is just the reality. Regular backups
and site replication rule.
And this actually concerns me... we help maintain some deployments
built by
Nice list.
You could add:
10. Dedup comes with a price.
Mike
On Sat, 2012-10-13 at 09:56 +0200, Roel_D wrote:
Thank you all for the good answers!
So if i put it all together :
1. ZFS is, in mirror and RAID configs, the best currently available option
for reliable data
2. Without
Some basic thoughts:
The one advantage of using a storage array instead of a JBOD is the
write cache when doing random writes. But the cost is that you loose the
data integrity features if the ZFS pool is not configured with
redundancy.
ZFS works best when it has multiple direct paths to
It is easy to understand that zfs srubs can be useful, But, How often do
we scrub or the equivalent of any other file system? UFS? VXFS?
NTFS? ...
ZFS has scrubs as a feature, but is it a need? I do not think so. Other
file systems accept the risk, mostly because they can not really do
anything if
Maybe people associate doing scrubs with something like
doing NTFS defrags?
Well if read all the posts and because i installed napp-it on my homeserver
which has a scrub scheduler i was almost at the point of assuming such.
I recently bought a secondhand x4140 just because it performs so well.
--- On Fri, 10/12/12, Michael Stapleton michael.staple...@techsologic.com
wrote:
I'm only writing this because I get the feeling some people
think scrubs
are a need. Maybe people associate doing scrubs with
something like
doing NTFS defrags?
I normally do scrubs when I think about
The problem is when people are overly paranoid because the feature
exists and end up causing problems by doing scrubs when they should not
because they feel they need to. Skilled admins also understand SLAs.
Mike
On Fri, 2012-10-12 at 14:38 -0700, Reginald Beardsley wrote:
--- On Fri,
On Fri, Oct 12, 2012 at 3:07 PM, Michael Stapleton
michael.staple...@techsologic.com wrote:
It is easy to understand that zfs srubs can be useful, But, How often do
we scrub or the equivalent of any other file system? UFS? VXFS?
NTFS? ...
If your data has checksums, it is standard practice to
But that the deal with mailing list everywhere. Be they OI or what ever
else.
Be it some problem someone is having, or some way to enhance a product,
or to get it to do something it was never intended to do.
Support mailing list and forums wouldn't exist if people didn't have
problems that the
So?}?\, a lot of people have already answered this in various ways.
I'm going to provide a little bit of direct answer and focus to some of
those other answers (and emphasis)
On 10/12/2012 5:07 PM, Michael Stapleton wrote:
It is easy to understand that zfs srubs can be useful, But, How often
I'm not a mathematician, but can anyone calculate the chance of the Same
8K datablock on Both submirrors Going bad on terabyte drives, before
the data is ever read and fixed automatically during normal read
operations?
And if you are not doing mirroring, you have already accepted a much
larger
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