On August 29, 2014 4:37:38 AM EDT, Dave Chinner <david@xxxxxxxxxxxxx> wrote: >On Fri, Aug 29, 2014 at 08:31:43AM +0200, Stefan Ring wrote: >> On Thu, Aug 28, 2014 at 1:07 AM, Dave Chinner <david@xxxxxxxxxxxxx> >wrote: >> > On Wed, Aug 27, 2014 at 12:14:21PM +0200, Marko Weber|8000 wrote: >> >> >> >> sorry dave and all other, >> >> >> >> can you guys recommend me the most stable / best mount options for >> >> my new server with ssd´s and XFS filesystem? >> >> >> >> at moment i would set: >defaults,nobarrier,discard,logbsize=256k,noikeep >> >> or is just "default" the best solution and xfs detect itself whats >best. >> >> >> >> can you guide me a bit? >> >> >> >> as eleavtor i set elevator=noop >> >> >> >> i setup disks with linux softraid raid1. On top of the raid is LVM >> >> (for some data partations). >> >> >> >> >> >> would be nice to hear some tipps from you >> > >> > Unless you have specific requirements or have the knowledge to >> > understand how the different options affect behaviour, then just >use >> > the defaults. >> >> Mostly agreed, but using "discard" would be a no-brainer for me. I >> suppose XFS does not automatically switch it on for non-rotational >> storage. > >Yup, you're not using your brain. :P > >mount -o discard *sucks* on so many levels it is not funny. I don't >recommend that anybody *ever* use it, on XFS, ext4 or btrfs. Just >use fstrim if you ever need to clean up a SSD. In particular trim is a synchronous command in many SSDs, I don't know about the impact on the kernel block stack. For the SSD itself that means the SSDs basically flush their write cache on every trim call. I often tell people to do performance testing with and without it and report back to me if they see no degradation caused by -o discard. To date no one has ever reported back. I think -o discard should have never been introduced and certainly not 5 years ago. In theory, SSDs that handle trim as a asynchronous command are now available, but I don't know any specifics. In any case, fstrim works for almost all workloads and doesn't have the potential continuous negative impact of -o discard. Greg -- Sent from my Android phone with K-9 Mail. Please excuse my brevity. _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
