On Wed, Jul 13, 2005 at 10:09:31PM -0400, I wrote: > I've seemingly hit a problem trying the combination of xfs on lvm on > raid10 (software) > > I've currently got 2 disks running (hda/hdc) and I've added two more > (hdi/hdk). > > My intention was to build a raid10 array. I made hdi1 a spare for md0, > and hdi2 a spare for md1. I made hdi3 and hdk3 a raid0 md2. I then made > md4 out of md2 and missing (md3 will be hda3 and hdc3). All fine.
Unfortunately, I had this backwards, and I built a raid 0+1 array. I've since rebuilt the array as raid0 (md5) over 3 raid1 (md2/3/4) arrays. > /proc/mdstat looks good, md4 is in degraded mode. The next step was > supposed to be make a fs on the lvm on raid10, copy what I can from the > corrupt old lvm partition, and then reformat hda3/hdc3 as raid devices > and raid 0 them (md3) and then add them into the raid1 (md4). First > problem, I had to reset the md detection flag in lvm.conf (lvm2). I > eventually was able to pvcreate, vgcreate, and lvcreate. When I went to > mkfs.xfs the new logical volume, I ran into: > > raid0_make_request bug: can't convert block across chunks or bigger than 64k > > > google reveals that error during kernel 2.5.x -> 2.6.x, back in 2003. It > seems to have been a problem with xfs on top of software raid0. > > http://www.ussg.iu.edu/hypermail/linux/kernel/0310.2/0982.html > and > http://linux-xfs.sgi.com/projects/xfs/mail_archive/200202/msg00472.html > > and perhaps fixed here: > http://marc.theaimsgroup.com/?l=linux-raid&m=106661294929434 > After reading some more, a few things clicked and I worked it out: # allow old PE size of 32m instead of 4m vgcreate -s 32m vg0 /dev/md5 # specify a smaller stripe unit for a raid device # from man mkfs.xfs mkfs.xfs -l su=32k /dev/vg0/video I also had a difficult time convincing lvm to use raid devices. In the end, I had to change /etc/lvm/lvm.conf as follows: # By default, LVM2 will ignore devices used as components of # software RAID (md) devices by looking for md superblocks. # 1 enables; 0 disables. md_component_detection = 1 } and the key to avoid the duplicate PV messages: # Exclude the cdrom and all disk partitions, only raid devices here filter = [ "r|/dev/cdrom|", "r|/dev/hd.*|" ] >From then, things went smoothly: pvdisplay --- Physical volume --- PV Name /dev/md5 VG Name vg0 PV Size 692.84 GB / not usable 0 Allocatable yes PE Size (KByte) 32768 Total PE 22171 Free PE 8987 Allocated PE 13184 PV UUID WjSblK-6c2d-w5ch-q4PP-K7Sd-rt14-Apa5M9 -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
