On 01/12/2015 06:56 PM, [email protected] wrote:
I have the root volume with several I/O intensive zones on an SSD drive.
Updating a file in one of the zones is noticeably going slow in comparison
how it was several months ago, while the file size hasn't changed much. I
suspect the SSD may need trimming.
Is the TRIM not available yet in smartos?
If so, what would be the right procedure of migrating the root volume with
its zones/* onto the different drive?
This advice may not help you since it sounds like you have your zones
pool on a single SSD rather than a mirrored pair, but perhaps it will
help someone with a similar problem.
We have some SmartOS machines with Intel SSDs, and some with Samsung
SSDs (I think it's the 840Pro ones, but I'm not certain). We haven't had
issues with the machines with the Intel SSDs, but we started seeing slow
I/O on some of the machines with the Samsungs.
As you guessed, illumos lacks trim support. Since I have a mirrored pool
I was able to do the following:
1. Offline one of the disks.
2. Pull it out, put it in a Linux machine and do this:
https://ata.wiki.kernel.org/index.php/ATA_Secure_Erase
3. Put it back in the SmartOS machine and put it back into the mirror
4. Wait for the mirror to resilver
5. Repeat for the other disk.
Performance was restored, though I anticipate the problem will recur at
some point. The long term plan is to replace those SSDs with Intel ones
that don't seem to degrade over time.
It would be nice to be able to issue that ATA command to the SSDs
directly from illumos, but at the moment I don't know how and the last
time I asked I didn't get very far.
So ideally, I would recommend buying a replacement SSD whose performance
won't degrade, attach it to the current drive to make a mirror, then
remove your current SSD from the pool and use it in a laptop with an OS
that supports TRIM.
Good luck!
-Nahum
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