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.
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
is partially or fully on this PV, what will happen.
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
and have begun to wonder what would happen in the case of a
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
VG, and then carving LVs out of that. We plan on using the CLVM
to fit into a clustered environment.
The arrays themselves are robust (RAID 5/6, redundant power
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,
bus, etc. in the iSCSI controller portion of the array, which will
downtime, but no true loss of data. Or someone may hit the wrong
switch and just reboot the thing, taking it offline for a short
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
intact when it comes back up. I suppose the analagous situation
be using LVM on a group of hot swap drives and pulling one of the
waiting a while, and then re-inserting it.
Can someone please walk me through the resulting steps that would
within LVM2 (or a GFS filesystem on top of that LV) in this
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