-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 David Brown wrote: > A simple lvm volume, mounted with XFS gives the following kernel > message: > > Filesystem "dm-11": Disabling barriers, not supported by the underlying > device > XFS mounting filesystem dm-11 So it does. I don't use XFS on my boxes & hadn't noticed this before. Turns out that xfs is checking barrier capabilities using queue->ordered in the device struct. If it has QUEUE_ORDERED_NONE, barriers are disabled (fs/xfs/linux-2.6/xfs_super.c). I'll look into why this is the case as given this check there shouldn't be any need for snap & mpath to check for barrier bios themselves. The patches that introduced those checks were submitted after problems were seen with barriers on these target types, so something was clearly submitting them at some stage. Kind regards, Bryn. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iD8DBQFGScUv6YSQoMYUY94RAh3sAKCpcTdyvLKpwni1VYssyo2cORBG6ACbBrbl xlJIlDXDdZGNAX5Tmjbt7RI= =yaL7 -----END PGP SIGNATURE----- _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
