On Sat, 20 Feb 2010 23:33:23 -0500 chris <tknchris@xxxxxxxxx> wrote: > Hello, > > I am trying to setup a raid 5+0 on 6 1TB sata disks. I created the > arrays like so: > > mdadm --create /dev/md2 --level=5 --raid-devices=2 /dev/sda /dev/sdb /dev/sdc > mdadm --create /dev/md3 --level=5 --raid-devices=2 /dev/sdd /dev/sde /dev/sdf > mdadm --create /dev/md4 --level=0 --raid-devices=2 /dev/md2 /dev/md3 > > The arrays create and sync fine, then I put lvm on top and create a > volume group and everything seems fine. I created 2 logical volumes > and formatted them with filesystems and initially didn't realize > anything was wrong. After running 2 virtual machines on them for a > while I noticed the vm's were reporting bad blocks on the volume. I > looked in the dom0 dmesg and found tons of messages such as: > > [444905.674655] raid0_make_request bug: can't convert block across > chunks or bigger than 64k 69314431 4 This looks like a bug in 'dm' or more likely xen. Assuming you are using a recent kernel (you didn't say), raid0 is receiving a request that does not fit entirely in on chunk, and which has more than on page in the bi_iovec. i.e. bi_vcnt != 1 or bi_idx != 0. As raid0 has a merge_bvec_fn, dm should not be sending bios with more than 1 page without first cheking that the merge_bvec_fn accepts the extra page. But the raid0 merge_bvec_fn will reject any bio which does not fit in a chunk. dm-linear appears to honour the merge_bvec_fn of the underlying device in the implementation of its own merge_bvec_fn. So presumably the xen client is not making the appropriate merge_bvec_fn call. I am not very familiar with xen: how exactly are you making the logical volume available to xen? Also, what kernel are you running? NeilBrown > > Chunksize for both raid5's and the raid0 is 64k so it would appear the > issue is not that the chunk size is greater than 64k. I also find it > hard to believe it could be any kind of lvm issue simply because the > message in dmesg clearly shows its related to the raid0. > > Any ideas on what I'm missing here would be greatly appreciated. I > would imagine it is some kind of alignment between block and chunk > sizes but I can't seem to figure it out :) > > More detailed information including raid information and errors is at > http://pastebin.com/f6a52db74 > > - chris > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
