Hi list, I posted this in to the xen list yesterday, however, I thought it may be more appropriate here. Let me know if I shouldn''t do this. I''m having a problem with mdraid running in a DomU. The issue is that mdraid declares one leg of the raid to have failed (when there''s actually nothing wrong). DomU is fc16 - 3.2.2-1.fc16.x86_64 Dom0 is fc14 - 2.6.32.26-174.2.xendom0.fc12.x86_64 (xen 4.0.1-7) The same DomU running on Dom0 fc16 - 3.2.7-1.fc16.x86_64 (xen 4.1.2-6) runs perfectly. This appears to be a known issue, however the resolution (which seems to be to disable barriers on the fly) doesn''t seem to work in this case. My question is: Is it possible to pass a parameter to the blkfront driver to ask it not to enable barrier during initialization? or is there another work around? [ 1.033058] blkfront: xvda: barrier: enabled [ 1.099153] xvda: xvda1 xvda2 [ 1.102871] blkfront: xvdb: barrier: enabled [ 1.130876] xvdb: xvdb1 xvdb2 [ 1.292692] md: bind<xvdb1> [ 1.413416] md: bind<xvda1> [ 1.419411] md: raid1 personality registered for level 1 [ 1.419836] bio: create slab <bio-1> at 1 [ 1.419953] md/raid1:md127: active with 2 out of 2 mirrors [ 1.419992] md127: detected capacity change from 0 to 7516180480 [ 1.424562] md127: unknown partition table [ 1.547284] EXT4-fs (md127): barriers disabled [ 1.553107] EXT4-fs (md127): mounted filesystem with ordered data mode. Opts: (null) [ 1.669483] dracut: Checking ext4: /dev/disk/by-label/rootfs [ 1.669592] dracut: issuing e2fsck -a /dev/disk/by-label/rootfs [ 1.690595] blkfront: barrier: empty write xvdb op failed [ 1.690611] blkfront: xvdb: barrier or flush: disabled [ 1.690628] end_request: I/O error, dev xvdb, sector 14682096 [ 1.690638] end_request: I/O error, dev xvdb, sector 14682096 [ 1.690646] md: super_written gets error=-5, uptodate=0 [ 1.690655] md/raid1:md127: Disk failure on xvdb1, disabling device. [ 1.690657] md/raid1:md127: Operation continuing on 1 devices. [ 1.690677] blkfront: barrier: empty write xvda op failed [ 1.690684] blkfront: xvda: barrier or flush: disabled [ 1.690696] end_request: I/O error, dev xvda, sector 14682096 [ 1.690705] end_request: I/O error, dev xvda, sector 14682096 [ 1.690713] md: super_written gets error=-5, uptodate=0 [ 1.692991] RAID1 conf printout: [ 1.692997] --- wd:1 rd:2 [ 1.693002] disk 0, wo:0, o:1, dev:xvda1 [ 1.693006] disk 1, wo:1, o:0, dev:xvdb1 [ 1.693010] RAID1 conf printout: [ 1.693013] --- wd:1 rd:2 [ 1.693016] disk 0, wo:0, o:1, dev:xvda1 [ 1.702896] dracut: rootfs: clean, 25635/454272 files, 293967/1835005 blocks [ 1.703682] dracut: Remounting /dev/disk/by-label/rootfs with -o ro [ 1.773347] EXT4-fs (md127): barriers disabled [ 1.774552] EXT4-fs (md127): mounted filesystem with ordered data mode. Opts: (null) [ 1.797159] dracut: Mounted root filesystem /dev/md127 [ 1.937620] dracut: Switching root