my 2c. fix me if i am wrong either activate the VG partially, and then all LVs on other PVs are still accessible. I remember these LVs will only have RO access. Though I have no idea why. use dm-zero to generate a fake PVs and add to VG, then allow VG to activate and access those LV. But i do not know if you access a LV that is partially or fully on this PV, what will happen. Ming On Tue, 2006-04-25 at 13:08 -0600, Ty! Boyack wrote: > I've been intrigued by the discussion of what happens when a PV fails, > and have begun to wonder what would happen in the case of a transient > failure of a PV. > > The design I'm thinking of is a SAN environment with several > multi-terabyte iSCSI arrays as PVs, being grouped together into a single > VG, and then carving LVs out of that. We plan on using the CLVM tools > to fit into a clustered environment. > > The arrays themselves are robust (RAID 5/6, redundant power supplies, > etc.) and I grant that if we lose the actual array (for example, if > multiple disks fail), then we are in the situation of a true and > possibly total failure of the PV and loss of it's data blocks. > > But there is always the possiblity that we could lose the CPU, memory, > bus, etc. in the iSCSI controller portion of the array, which will cause > downtime, but no true loss of data. Or someone may hit the wrong power > switch and just reboot the thing, taking it offline for a short time. > Yes, that someone would probably be me. Shame on me. > > The key point is that the iSCSI disk will come back in a few > minutes/hours/days depending on the failure type, and all blocks will be > intact when it comes back up. I suppose the analagous situation would > be using LVM on a group of hot swap drives and pulling one of the disks, > waiting a while, and then re-inserting it. > > Can someone please walk me through the resulting steps that would happen > within LVM2 (or a GFS filesystem on top of that LV) in this situation? > > Thanks, > > -Ty! > _______________________________________________ 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/
