As a follow-up to my own question : Some answers off-list seem to imply that it is not so much shared access to the SAN-shared LVM2 volume group that is the issue, it is the worry of two or more systems updating the LVM metadata at the same time. I just want to clarify that assuming this can be mitigated by only ever updating the metadata (creating,deleting,resizing volumes etc.) on one server, is this safe ? Thanks, -Mark -----Original Message----- From: linux-lvm-bounces@redhat.com [mailto:linux-lvm-bounces@redhat.com] On Behalf Of Mark Round Sent: 16 September 2009 17:05 To: linux-lvm@redhat.com Subject: Shared access to LVM2 metadata Hi all, Quick question - is this page : http://tldp.org/HOWTO/LVM-HOWTO/sharinglvm1.html only applicable to LVM1, and not LVM2 ? I suspect that it is, based on the URL and my own experiments but would like to be certain. The reason I ask is that I have a number of hosts on a SAN (Xen Dom0 systems), which utilise a shared block device. I want to create a volume group on this block device, and split this up into LVMs for each virtual machine. The Dom0 systems would then see all volumes, although each volume would only be active and mounted on one host at a time. I have run my own tests, and I can see that if I create, modify or delete logical volumes within a shared volume group on one host, the changes are immediately reflected on another (e.g. "lvcreate" on one host shows the volume immediately on the other host with "lvs"). I have tried creating, resizing, delete, and performing various file-system related activity on this shared volume group, and I haven't run into any kind of LVM metadata or filesystem corruption, and was happy to put this into production. But the stark warnings in that document made me wary - am I missing something ? Am I risking some form of latent LVM2 metadata corruption ? Googling around didn't produce a definitive answer, so I apologise if this has already been asked before. Many thanks, -Mark _______________________________________________ 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/
