I have a xen vps, which I just upgraded to the new LTS 12 Precise Pangolin.
However, I see this error on booting:
[ 12.848076] end_request: I/O error, dev xvda, sector 12841 [ 12.848093] end_request: I/O error, dev xvda, sector 12841 [ 12.848103] Buffer I/O error on device xvda1, logical block 1605 [ 12.848110] lost page write due to I/O error on xvda1 [ 12.848129] Aborting journal on device xvda1.
Results in / being mounted read-only. Reboot:
[ 3.087257] EXT3-fs (xvda1): warning: ext3_clear_journal_err: Marking fs in need of filesystem check. [ 3.087677] EXT3-fs (xvda1): recovery complete [ 3.088514] EXT3-fs (xvda1): mounted filesystem with ordered data mode Begin: Running /scripts/local-bottom ... done. done. Begin: Running /scripts/init-bottom ... done. fsck from util-linux 2.20.1 PRGMRDISK1 contains a file system with errors, check forced. Checking disk drives for errors. This may take several minutes. Press C to cancel all checks in progress PRGMRDISK1: ***** REBOOT LINUX ***** PRGMRDISK1: 371152/6001184 files (2.8% non-contiguous), 4727949/12000000 blocks mountall: fsck /  terminated with status 3 mountall: System must be rebooted: / [ 151.566949] Restarting system. Name ID Mem VCPUs State Time(s) shadowmint 236 2048 1 --p--- 0.0
Reboot -> back to 1.
This is definitely an issue with the 3.2 kernel, because booting the 3.0.0 or 2.6.38 kernel series make this issue magically disappear.
I'm certain this is some kind of weird xen thing, but no idea.
Anyhow, until this is resolve I strongly recommend against upgrading if you're running a xen server.