Dave wrote: > Hello, > > I believe I might be misunderstanding whether vgimport and vgexport are needed in my > particular situation. It would be great to get some feedback for clarification. > > THE SETUP: > > LVM1 (1.0.8-14) on two RedHat AS3 systems (kernel: 2.4.21-47.ELsmp). > I think the same concept applies for LVM2 as well though. > Machine A is primary and Machine B is backup in a two-node Linux heartbeat cluster. > Both machines are connected to the same SAN via fiber, and see the same disks, where > the volume groups reside. > > THE STRATEGY: > > The idea is for A to have the LVM file systems mounted, and when a failure is > detected, have the LVM file systems "moved" to (or seen by) system B. The way this > is currently accomplished is for A to do the following upon detection of a failure: > > + unmount file systems > + deactivate (vgchange -an $vg) > + export (vgexport $vg) > > then, on system B: > > + import & activate (vgimport $vg $disks) > + mount file systems > > THE ISSUE: > > The export works as expected on A, but upon import on B, a return code of 4 is > returned meaning "volume group already exists". The mounting works properly, but > all the disks are shown like this: > > "inactive PV /dev/sdx is in EXPORTED VG $vg" > > when inspected with pvscan. > > > Does a vgimport and/or vgexport mark the disks themselves, or simply update the > system on which the commands are run??? I suppose that is essentially the heart of > this issue. Yes, vgimport/export marks the disks in the volume group. It's really for moving disks between systems where the target system might have a volume group with the same name as the one to be imported. > I'm starting to believe that for our strategy the vgexport and vgimport commands are > not necessary, and are actually causing the problem. (The HOWTO mentions these > commands are used to move disks between systems, but perhaps that is meant to refer > to disks that are only physically moved?) > > Instead, the following strategy might be correct in case system A fails (Note: no > vgimport or vgexport commands): > > + unmount fs > + vgchange -an $vg > > then, on system B: > > + vgchange -ay $vg > + mount fs > > > IS THIS CORRECT??? > Yes. IF YOU'RE VERY CAREFUL! vgimport/vgexport are not the tools you want for this job. -- patrick _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
