----- Original Message ---- > From: J. Roeleveld <[email protected]> > On Thu, April 7, 2011 7:31 pm, BRM wrote: > > The attraction to LVM for me was that from what I could tell it supported > > and > > implemented a software-RAID > > so that I could help protect from disk-failure. I never got around to > > configuring that side of it, but that was my goal. > > Or are you saying I was misunderstanding and LVM _does not_ contain > > software-RAID support? > > Unless I am mistaken, LVM does not provide redundancy. It provides > disk-spanning (JBOD) and basic striping (RAID-0). > > For redundancy, I would use a proper RAID (either hardware or software). > On top of this, you can then decide to have a single filesystem, LVM or > even partition this. > > I think the confusion might have come from the fact that both LVM and > Linux Software Raid use the "Device Mapper" interface in the kernel config > and they are in the same part. > > Also, part of the problem is that striping is also called RAID-0. That, to > people who don't fully understand it yet, makes it sound like it is a > RAID. > It actually isn't as it doesn't provide any redundancy.
I think the issue comes from the fact that LVM2 supports Mirroring without an underlying RAID controller: http://tinyurl.com/3woh2d7 http://en.wikipedia.org/wiki/Logical_Volume_Manager_%28Linux%29 http://www.gossamer-threads.com/lists/gentoo/performance/59776 Which would be a redundancy. > > I do hope you didn't loose too much important data when you had this issue. > No, I didn't loose any important data (fortunately). If I did, I would have paid for the drive to be recovered; it was mostly portage, var/tmp, some extra sandbox stuff, kind of things. Ben
