On Sat, 24 Oct 2009, Bob Friesenhahn wrote:
Is solaris incapable of issuing a SATA command FLUSH CACHE EXT?
It issues one for each update to the intent log.
I should mention that FLASH SSDs without a capacitor/battery-backed
cache flush (like the X25-E) are likely to get burned out pretty
On Fri, 23 Oct 2009, Eric D. Mudama wrote:
I don't believe the above statement is correct.
According to anandtech who asked Intel:
http://www.anandtech.com/cpuchipsets/intel/showdoc.aspx?i=3403&p=10
the DRAM doesn't hold user data. The article claims that data goes
through an internal 256KB
On Tue, Oct 20 at 22:24, Frédéric VANNIERE wrote:
You can't use the Intel X25-E because it has a 32 or 64 MB volatile
cache that can't be disabled neither flushed by ZFS.
I don't believe the above statement is correct.
According to anandtech who asked Intel:
http://www.anandtech.com/cpuchips
Interesting. We must have different setups with our PERCs. Mine have
always auto rebuilt.
--
Scott Meilicke
On Oct 22, 2009, at 6:14 AM, "Edward Ned Harvey"
wrote:
Replacing failed disks is easy when PERC is doing the RAID. Just
remove
the failed drive and replace with a good one, and t
On Thu, 22 Oct 2009, Marc Bevand wrote:
Bob Friesenhahn simple.dallas.tx.us> writes:
For random write I/O, caching improves I/O latency not sustained I/O
throughput (which is what random write IOPS usually refer to). So Intel can't
cheat with caching. However they can cheat by benchmarking a b
Actually, I think this is a case of crossed wires. This issue was reported a
while back on a news site for the X25-M G2. Somebody pointed out that these
devices have 8GB of cache, which is exactly the dataset size they use for the
iops figures.
The X25-E datasheet however states that while wr
> The Intel specified random write IOPS are with the cache enabled and
> without cache flushing. They also carefully only use a limited span
> of the device, which fits most perfectly with how the device is built.
How do you know this? This sounds much more detailed than any average
person could
> Replacing failed disks is easy when PERC is doing the RAID. Just remove
> the failed drive and replace with a good one, and the PERC will rebuild
> automatically.
Sorry, not correct. When you replace a failed drive, the perc card doesn't
know for certain that the new drive you're adding is mea
Bob Friesenhahn simple.dallas.tx.us> writes:
>
> The Intel specified random write IOPS are with the cache enabled and
> without cache flushing.
For random write I/O, caching improves I/O latency not sustained I/O
throughput (which is what random write IOPS usually refer to). So Intel can't
ch
On Tue, 20 Oct 2009, [UTF-8] Fr??d??ric VANNIERE wrote:
> You can't use the Intel X25-E because it has a 32 or 64 MB volatile cache
> that can't be disabled neither flushed by ZFS.
Say what? My understanding is that the officially supported Sun SSD for the
x4540 is an OEM'd Intel X25-E, so I don'
On Wed, October 21, 2009 12:53, Bob Friesenhahn wrote:
> On Wed, 21 Oct 2009, David Dyer-Bennet wrote:
>>>
>>> Device performance should be specified as a minimum assured level of
>>> performance and not as meaningless "peak" ("up to") values. I repeat:
>>> peak values are meaningless.
>>
>> Seem
On Wed, 21 Oct 2009, David Dyer-Bennet wrote:
Device performance should be specified as a minimum assured level of
performance and not as meaningless "peak" ("up to") values. I repeat:
peak values are meaningless.
Seems a little pessimistic to me. Certainly minimum assured values are
the bas
On Wed, October 21, 2009 12:21, Bob Friesenhahn wrote:
>
> Device performance should be specified as a minimum assured level of
> performance and not as meaningless "peak" ("up to") values. I repeat:
> peak values are meaningless.
Seems a little pessimistic to me. Certainly minimum assured val
On Wed, 21 Oct 2009, Marc Bevand wrote:
Bob Friesenhahn simple.dallas.tx.us> writes:
[...]
X25-E's write cache is volatile), the X25-E has been found to offer a
bit more than 1000 write IOPS.
I think this is incorrect. On the paper the X25-E offers 3300 random write
4kB IOPS (and Intel is kn
On Oct 20, 2009, at 10:24 PM, Frédéric VANNIERE wrote:
The ZIL is a write-only log that is only read after a power failure.
Several GB is large enough for most workloads.
You can't use the Intel X25-E because it has a 32 or 64 MB volatile
cache that can't be disabled neither flushed by ZFS.
Ed, your comment:
>If solaris is able to install at all, I would have to acknowledge, I
>have to shutdown anytime I need to change the Perc configuration, including
>replacing failed disks.
Replacing failed disks is easy when PERC is doing the RAID. Just remove the
failed drive and replace with
Thanks Frédéric, that is a very interesting read.
So my options as I see them now:
1. Keep the x25-e, and disable the cache. Performance should still be improved,
but not by a *whole* like, right? I will google for an expectation, but if
anyone knows off the top of their head, I would be app
> Thanks Ed. It sounds like you have run in this mode? No issues with
> the perc?
> >
> > You can JBOD with the perc. It might be technically a raid0 or
> > raid1 with a
> > single disk in it, but that would be functionally equivalent to JBOD.
The only time I did this was ...
I have a Windows se
Thanks Ed. It sounds like you have run in this mode? No issues with
the perc?
--
Scott Meilicke
On Oct 20, 2009, at 9:59 PM, "Edward Ned Harvey"
wrote:
System:
Dell 2950
16G RAM
16 1.5T SATA disks in a SAS chassis hanging off of an LSI 3801e, no
extra drive slots, a single zpool.
svn_124
Thank you Bob and Richard. I will go with A, as it also keeps things simple.
One physical device per pool.
-Scott
On 10/20/09 6:46 PM, "Bob Friesenhahn" wrote:
> On Tue, 20 Oct 2009, Richard Elling wrote:
>>
>> The ZIL device will never require more space than RAM.
>> In other words, if you o
What makes you say that the X25-E's cache can't be disabled or flushed?
The net seems to be full of references to people who are disabling the
cache, or flushing it frequently, and then complaining about the
performance!
T
Frédéric VANNIERE wrote:
The ZIL is a write-only log that is only read
Bob Friesenhahn simple.dallas.tx.us> writes:
> [...]
> X25-E's write cache is volatile), the X25-E has been found to offer a
> bit more than 1000 write IOPS.
I think this is incorrect. On the paper the X25-E offers 3300 random write
4kB IOPS (and Intel is known to be very conservative about the
The ZIL is a write-only log that is only read after a power failure. Several GB
is large enough for most workloads.
You can't use the Intel X25-E because it has a 32 or 64 MB volatile cache that
can't be disabled neither flushed by ZFS.
Imagine your server has a power failure while writing da
> System:
> Dell 2950
> 16G RAM
> 16 1.5T SATA disks in a SAS chassis hanging off of an LSI 3801e, no
> extra drive slots, a single zpool.
> svn_124, but with my zpool still running at the 2009.06 version (14).
>
> My plan is to put the SSD into an open disk slot on the 2950, but will
> have to co
On Tue, 20 Oct 2009, Richard Elling wrote:
The ZIL device will never require more space than RAM.
In other words, if you only have 16 GB of RAM, you won't need
more than that for the separate log.
Does the wasted storage space annoy you? :-)
What happens if the machine is upgraded to 32GB of
On Oct 20, 2009, at 4:44 PM, Bob Friesenhahn wrote:
On Tue, 20 Oct 2009, Scott Meilicke wrote:
A. Use all 32G for the ZIL
B. Use 8G for the ZIL, 24G for an L2ARC. Any issues with slicing up
an SSD like this?
C. Use 8G for the ZIL, 16G for an L2ARC, and reserve 8G to be used
as a ZIL for th
On Tue, 20 Oct 2009, Scott Meilicke wrote:
A. Use all 32G for the ZIL
B. Use 8G for the ZIL, 24G for an L2ARC. Any issues with slicing up an SSD like
this?
C. Use 8G for the ZIL, 16G for an L2ARC, and reserve 8G to be used as a ZIL for
the future zpool.
Since my future zpool would just be use
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