share logical volumes but not simul

[Ravinder Kaul]

Is it possible for two servers to use the same LV in a VG on a disk array if we unmount the LV from one machine and mount it on the other. i.e is the following procedure O.K.
On server 1
VG01 on a disk array connected to two servers.
/dev/VG01/lv-test mounted on /test
vgexport -p -s -v -m /dev/VG01
umount /test
rcp server 2On Server 2
mkdir /dev/VG01
mknod /dev/VG01/group c 64 0x0n0000
vgimport -v -s -m /dev/VG01
vgchange -a y VG01
mount /dev/VG01/lv-test /test
Disk paths are the same in both the servers

[Michael Tully]

In between the vgchange and the mount, you will need to run an 'fsck' on the volume.

[Michael Tully]

I should have read your question more closely. You can have access to the LUN's from both servers, BUT one of the servers can only be set up as read-only. Only other way is to use NFS mount points, then you have write access from both servers. Only drawback to this is you are also relying on the network. I wish I could provide some examples, but I'm not near a system.

[Pete Randall]

The process you describe will work: the machines can share the volume but only one will be able to have access at any one time. However, I believe you're going to have to deactivate the vg before the export, so the sequence would be:
umount /test
vgchange -a n VG01
vgexport -p -s -v -m /dev/VG01rcp server 2On Server 2
mkdir /dev/VG01
mknod /dev/VG01/group c 64 0x0n0000
vgimport -v -s -m /dev/VG01
vgchange -a y VG01
mount /dev/VG01/lv-test /test

And, as Michael said, you may have to run a fsck.


Pete

[Ravinder Kaul]

Michael

That should(RO mount) be reqd if the LV is to be accessible from both servers and it will make all the lvs in the vg RO. I want to know that is it OK for a vg to be activated on both servers while the LVs defined in that VG are available from either of the servers but not both. say we had created a vg on a disk array and using 4 lvs in it on server 1 . We unmount two of the lvs in server 1 Then export the vg in preview mode , import the vg to another server and activate it there. and mount the unmounted lvs of server 1 on server 2 and use the data in the lvs on server 2. Is this procedure OK or there are any pitfalls

Thanks
RK