Thanks guys for the pointers to this Intel thread:
https://communities.intel.com/thread/77801
It looks promising. I intend to update the firmware on disks in one node tonight and will report back after a few days to a week on my findings.
I've also posted to that forum and will update there too.
Regards,
Richard
Hi Everyone,
We have a Ceph pool that is entirely made up of Intel S3700/S3710 enterprise SSD's.
We are seeing some significant I/O delays on the disks causing a “SCSI Task Abort” from the OS. This seems to be triggered by the drive receiving a “Synchronize cache command”.
My current thinking is that setting nobarriers in XFS will stop the drive receiving a sync command and therefore stop the I/O delay associated with it.
In the XFS FAQ it looks like the recommendation is that if you have a Battery Backed raid controller you should set nobarriers for performance reasons.
Our LSI card doesn’t have battery backed cache as it’s configured in HBA mode (IT) rather than Raid (IR). Our Intel s37xx SSD’s do have a capacitor backed cache though.
So is it recommended that barriers are turned off as the drive has a safe cache (I am confident that the cache will write out to disk on power failure)?
Has anyone else encountered this issue?
Any info or suggestions about this would be appreciated.
Regards,
Richard
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