On Tuesday 15 June 2010 04:52:10 Stan Hoeppner wrote: > Boyd Stephen Smith Jr. put forth on 6/14/2010 10:45 AM: > > On Monday 14 June 2010 03:11:56 Gerald C.Catling wrote: > >> Hi Guy's, > >> I am not a Debian user but I have seen references to LVM here. > >> I have 3 drives LVM'd to give me 1.3TB of storage space on my server. > >> The first drive of this set has died. > > > > Mostly, when one of your physical volumes is irrecoverably lost, so is > > any logical volume whose logical extents corresponded to one of the lost > > physical extents. > > This is why one should only use LVM on top of real hardware or software > RAID or a big SAN LUN. You should use LVM on top of whatever you have. It's vastly superior to partitioning as a way to divide a disk. Even if you do not need to divide a disk, the adds snapshotting and an on-line migration path above just using the disk. That said, any data you care about should have some form of single-disk redundancy (at least) AND a backup plan. > Using LVM for what most in the IT world have > typically called "disk spanning", which has been around for over 2 > decades, is a recipe for trouble in the absence of a good backup/recovery > procedure, as the OP has unfortunately discovered. My introduction to LVM was partially on Linux, where the disk spanning capabilities are the most talked about feature, but also some from the HP-UX side, where we used LVM for handling the mirroring of drives, instead of a separate RAID sub-system or card. I think the Linux LVM documentation is fairly clear that a VG will not normally activate unless all its member PVs are available. > mirroring them with mdadm. I also recommend using mdadm to manage your RAID. I've had it handle 0, 1, and 5 quite well. It also supports RAID 6 and some exotic variants on RAID 1/0. -- Boyd Stephen Smith Jr. ,= ,-_-. =. bss@iguanasuicide.net ((_/)o o(\_)) ICQ: 514984 YM/AIM: DaTwinkDaddy `-'(. .)`-' http://iguanasuicide.net/ \_/
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