Am Freitag, 8. März 2013 schrieb Dave Chinner: > On Thu, Mar 07, 2013 at 02:15:31PM +0100, Julien FERRERO wrote: > > > We actually test brutal "Power off" for xfs, ext4 and other file > > > systems. If your storage is configured properly and you have > > > barriers enabled, they all pass without corruption. > > > > > > What hardware raid cards can do is to hide a volatile write cache. > > > Either on the raid HBA itself or, even worse, on the backend disks > > > behind the card. S-ata disks tend to default to write cache enabled > > > and need to be checked especially careful (sas drives tend to be > > > write cache disabled by default). > > > > > > > > Write cache is supposed to be disabled on the H/W RAID (according to > > hdparm) and barrier are correctly enabled since xfs does not report > > any warning at mount. > > > > > > > > The odd thing is we never see this with kernel 2.6.18 where barriers > > weren't yet available. > > Yes they were. XFS had barrier support added in 2.6.15. I thought this was 2.6.16? Or was that the kernel where it became usable due to the generic write barrier part being merged while the XFS one was ready earlier? I still remember the XFS filesystem crashes I had back then that went away with disabling the write cache of the drive in my ThinkPad T42 back then and where solved with 2.6.17, whereas 2.6.17.7 solved a directory corruption issue introduced with 2.6.17. Thus I always recommended at least 2.6.17.7 in case of write barrier usage with XFS. Thanks, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7 _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
