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 On 5 September 2015 at 07:55, Richard Bade <hitr...@gmail.com> wrote: > 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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