On 9/2/15 9:24 PM, Richard Bade wrote: > Hi Everyone, I have a question about nobarriers. 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 s3710 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)? If you have a device which guarantees that every acknowledged write will persist even if power is lost, then you can safely turn off barriers. > The reason I am asking about this is that 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 no > barriers will stop the drive receiving a sync command and therefore > stop the I/O delay associated with it. Interesting, I thought that usually devices with battery-backed cache will just ignore synchronize cache commands. But if not, then sure, maybe that's the issue. -Eric > This is happening on our Ceph storage cluster. For those not familiar > with Ceph, it uses XFS as the underlying filesystem for the object > stores. > > Has anyone else encountered this issue? Any info or suggestions about > this would be appreciated. > > Regards, Richard > > > > _______________________________________________ xfs mailing list > xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs > _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
