-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Fri, 24 Oct 2003, Gert van der Knokke wrote: > Rickard Olsson wrote: > > John> If you had just a simple concatenation of all the disks, then > > you are > > John> toast. How do you expect LVM to restore the missing 60gb if > > there's > > John> no parity information or mirrored blocks? It's impossible! > > I didn't expect lvm to restore the missing data, I guessed it would just > let me access the rest of the data. To elaborate a bit, there are three cases to consider: o An LV with no extents stored on the failed drive. This LV is intact and LVM should be able to provide it as if nothing had happened, because nothing *has* happened to this LV. o An LV all of whose extents were stored on the failed drive. This LV's content is entirely lost and may only be recovered from other media. o An LV, some but not all of whose extents were stored on the failed drive. Once the lost storage has been replaced, LVM *could* present this LV, which would contain a damaged filesystem. 'fsck' might be able to repair the filesystem enough to recover files which were stored in the undamaged extents, or a filesystem debugger might be available to facilitate manual recovery. Some of the content is lost and may only be recovered from other media, but other content is undamaged. I don't yet know LVM well enough to say whether it *does* handle this case, but it can in theory and I would expect it to be written to do so. Others' comments suggest that this is so. BTW I've used various logical-volume schemes for years on top of hardware RAID. It's a combination that works well. I don't understand why some people want to put (soft) RAID on top of LVM rather than underneath it. - -- Mark H. Wood, Lead System Programmer mwood@IUPUI.Edu MS Windows *is* user-friendly, but only for certain values of "user". -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.2 (GNU/Linux) Comment: pgpenvelope 2.10.2 - http://pgpenvelope.sourceforge.net/ iD8DBQE/nn9/s/NR4JuTKG8RArSyAJ93Bdog6U2fNrbpF/dAJ6BZOVlMyQCeKhmU fEB18by5nkGWlKt/Ge35olE= =8ETo -----END PGP SIGNATURE----- _______________________________________________ linux-lvm mailing list linux-lvm@sistina.com http://lists.sistina.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
