netz-haut - stephan seitz
2011-May-05 08:14 UTC
AW: [Xen-users] debian Lenny -> Squeeze domU mdX software raidmigration - failed to assemble arrays
Hi, to make transitions more convenient, I've done this by using uuid instead of device names. If you ls -l /dev/disk/by-uuid inside your domU, you'll see something like lrwxrwxrwx 1 root root 10 5. Mai 07:38 39a2a64b-0716-47ad-92f4-a7437cac54ee -> ../../sda2 lrwxrwxrwx 1 root root 10 5. Mai 07:38 e8b97b59-a790-417c-8231-fe8da8b6e6ee -> ../../sda1 In /etc/fstab inside the domU, '/dev/sda2' would be replaced by 'UUID=39a2a64b-0716-47ad-92f4-a7437cac54ee' and '/dev/sda1' by 'UUID=e8b97b59-a790-417c-8231-fe8da8b6e6ee' If pvgrub or pygrub is used, the devicename needs to be replaced inside the domU in /boot/grub/menu.lst from e.g. 'root=/dev/sda2' to 'root=UUID=39a2a64b-0716-47ad-92f4-a7437cac54ee' If, like in your case, the domU kernel is directly booted by a cfg statement, the root statement needs to be changed in the cfg file by using the the same formatting as in the menu.lst above. Now, it doesn't matter any longer if the device is called xvda or sda or (ancient but possible) hda. Indeed, there are xenified kernels out in the wild which doesn't respect the UUID... but I've never seen problems with recent kernels. Cheers, Stephan Btw. Maybe someone knows if a similar abstraction is possible for tty0 vs tty1 vs hvc0 vs xvc0 ?> Von: xen-users-bounces@lists.xensource.com [mailto:xen-users- > bounces@lists.xensource.com] Im Auftrag von Cameron Camp > Gesendet: Dienstag, 3. Mai 2011 20:08 > An: Joseph Glanville > Cc: xen-users@lists.xensource.com > Betreff: Re: [Xen-users] debian Lenny -> Squeeze domU mdX software > raidmigration - failed to assemble arrays > > Yes, my whatever.domain.cfg was insane, I fixed it by leaving: > > root = /dev/xvda2 > > but had to update: > > #kernel = '/boot/vmlinuz-2.6.26-1-xen-amd64' > #ramdisk = '/boot/initrd.img-2.6.26-1-xen-amd64' > kernel = '/boot/vmlinuz-2.6.32-5-xen-amd64' > ramdisk = '/boot/initrd.img-2.6.32-5-xen-amd64' > > after that it booted with errors, but allowed me to > vi /etc/apt/sources.lists in DomU and change lenny to squeeze and then > update/upgrade, and now my DomU Debian Lenny is Squeeze :) > > No idea why the kernel mismatch would result in an md/sd/xvd error, but > hope this helps someone else! > > Thx, > Cameron > > > On Wed, 2011-05-04 at 03:11 +1000, Joseph Glanville wrote: > > Hi Cameron > > > > > > Can you please post your domU xen configuration file, also at the > > initramfs prompt can you type and post output of: > > cat /proc/cmdline > > > > > > I think you have incorrectly configured the target of the root disk. > > > > > > Kind regards. > > Joseph. > > > > On 3 May 2011 03:12, Cameron Camp <cameron@campworkz.com> wrote: > > I got the previous migration with standard /dev/sdX Dom0 to > > work by > > changing > > > > /dev/sda2 > > > > to > > > > /dev/xvda2 > > > > in /etc/xen/whatever.domain.com.cfg > > > > but now I'm migrating Lenny DomU VM to a Squeeze Dom0 which > > uses > > software raid filesystem like: > > > > /dev/md2 > > > > but DomU > > uses /dev/sda2 /home/xen/domains/whatever.domain.com/disk.img > > still, and won't see the proper hdd, I get: > > > > mount: mounting none on /dev failed: No such device > > W: devtmpfs not available, falling back to tmpfs for /dev > > Couldnt get a file descriptor referring to the console > > KDGKBMODE: Bad file descriptor > > loadkeys: error reading keyboard mode > > Begin: Loading essential drivers ... done. > > Begin: Running /scripts/init-premount ... done. > > Begin: Mounting root file system ... Begin: > > Running /scripts/local-top ... Begin: Loading[ 1.304655] > > md: raid1 > > personality registered for level 1 > > Success: loaded module raid1. > > done. > > Begin: Assembling all MD arrays ... Failure: failed to > > assemble all > > arrays. > > done. > > done. > > Begin: Waiting for root file system ... done. > > Gave up waiting for root device. Common problems: > > - Boot args (cat /proc/cmdline) > > - Check rootdelay= (did the system wait long enough?) > > - Check root= (did the system wait for the right device?) > > - Missing modules (cat /proc/modules; ls /dev) > > ALERT! /dev/xvda2 does not exist. Dropping to a shell! > > > > > > BusyBox v1.17.1 (Debian 1:1.17.1-8) built-in shell (ash) > > Enter 'help' for a list of built-in commands. > > > > /bin/sh: can't access tty; job control turned off > > (initramfs) > > ================================> > it seems like I somehow don't have the right "driver" loading > > in DomU to > > see Dom0 md2 filesystem, but couldn't find anything > > in /boot/whatever > > (or even /boot) in DomU where I could pass an argument to > load > > whatever, > > is there something in the whatever.domain.com.cfg I can set > to > > specify > > md2 on Dom0 filesystem to be recognized by DomU? > > > > Thanks, > > Cameron > > > > > > _______________________________________________ > > Xen-users mailing list > > Xen-users@lists.xensource.com > > http://lists.xensource.com/xen-users > > > > > > > > -- > > Kind regards, > > Joseph. > > > > > > Founder | Director > > > > Orion Virtualisation Solutions | www.orionvm.com.au | Phone: 1300 56 > > 99 52 | Mobile: 0428 754 846 > > > > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Simon Hobson
2011-May-05 10:10 UTC
Re: AW: [Xen-users] debian Lenny -> Squeeze domU mdX software raidmigration - failed to assemble arrays
netz-haut - stephan seitz wrote:>to make transitions more convenient, I''ve done this by using uuid >instead of device names. >If you ls -l /dev/disk/by-uuid inside your domU, you''ll see something like > >lrwxrwxrwx 1 root root 10 5. Mai 07:38 >39a2a64b-0716-47ad-92f4-a7437cac54ee -> ../../sda2 >lrwxrwxrwx 1 root root 10 5. Mai 07:38 >e8b97b59-a790-417c-8231-fe8da8b6e6ee -> ../../sda1 > >In /etc/fstab inside the domU, ''/dev/sda2'' would be replaced by >''UUID=39a2a64b-0716-47ad-92f4-a7437cac54ee'' and ''/dev/sda1'' by >''UUID=e8b97b59-a790-417c-8231-fe8da8b6e6ee'' > >If pvgrub or pygrub is used, the devicename needs to be replaced >inside the domU in /boot/grub/menu.lst from e.g. ''root=/dev/sda2'' to >''root=UUID=39a2a64b-0716-47ad-92f4-a7437cac54ee'' > >If, like in your case, the domU kernel is directly booted by a cfg >statement, the root statement needs to be changed in the cfg file by >using the the same formatting as in the menu.lst above. > >Now, it doesn''t matter any longer if the device is called xvda or >sda or (ancient but possible) hda.Would using labels be more convenient ? At least on ext2/3, dunno about others. If you should move a guest to another host, or rebuild it''s filesystem for any reason, setting a label on the filesystem is probably easier than finding the places (multiple - Dom0 and DomU) places the UUID has been used. -- Simon Hobson Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed author Gladys Hobson. Novels - poetry - short stories - ideal as Christmas stocking fillers. Some available as e-books. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Joseph Glanville
2011-May-05 17:35 UTC
Re: AW: [Xen-users] debian Lenny -> Squeeze domU mdX software raidmigration - failed to assemble arrays
Hi, It really depends, personally if you are specifying the targets of the disks in the xen config file the device will be persistent across any amount of reboots and addition of new disks so the use of UUIDs or LABELs isn''t really all that beneficial in my view. Especially if you want the ability to clone the volume or back it up via mounting the disk and taring it up etc. I still find good old fashioned paths the best way: /dev/xvda1 etc. Joseph. On 5 May 2011 20:10, Simon Hobson <linux@thehobsons.co.uk> wrote:> netz-haut - stephan seitz wrote: > >> to make transitions more convenient, I''ve done this by using uuid instead >> of device names. >> If you ls -l /dev/disk/by-uuid inside your domU, you''ll see something like >> >> lrwxrwxrwx 1 root root 10 5. Mai 07:38 >> 39a2a64b-0716-47ad-92f4-a7437cac54ee -> ../../sda2 >> lrwxrwxrwx 1 root root 10 5. Mai 07:38 >> e8b97b59-a790-417c-8231-fe8da8b6e6ee -> ../../sda1 >> >> In /etc/fstab inside the domU, ''/dev/sda2'' would be replaced by >> ''UUID=39a2a64b-0716-47ad-92f4-a7437cac54ee'' and ''/dev/sda1'' by >> ''UUID=e8b97b59-a790-417c-8231-fe8da8b6e6ee'' >> >> If pvgrub or pygrub is used, the devicename needs to be replaced inside >> the domU in /boot/grub/menu.lst from e.g. ''root=/dev/sda2'' to >> ''root=UUID=39a2a64b-0716-47ad-92f4-a7437cac54ee'' >> >> If, like in your case, the domU kernel is directly booted by a cfg >> statement, the root statement needs to be changed in the cfg file by using >> the the same formatting as in the menu.lst above. >> >> Now, it doesn''t matter any longer if the device is called xvda or sda or >> (ancient but possible) hda. > > Would using labels be more convenient ? At least on ext2/3, dunno about > others. > > If you should move a guest to another host, or rebuild it''s filesystem for > any reason, setting a label on the filesystem is probably easier than > finding the places (multiple - Dom0 and DomU) places the UUID has been used. > > -- > Simon Hobson > > Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed > author Gladys Hobson. Novels - poetry - short stories - ideal as > Christmas stocking fillers. Some available as e-books. > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users >-- Kind regards, Joseph. Founder | Director Orion Virtualisation Solutions | www.orionvm.com.au | Phone: 1300 56 99 52 | Mobile: 0428 754 846 _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users