On Thursday 07 April 2011 06:52:26 BRM wrote: > ----- Original Message ---- > > > From: Joost Roeleveld <jo...@antarean.org> > > > > On Thursday 07 April 2011 06:20:55 BRM wrote: > > > ----- Original Message ---- > > > > > > > From: Neil Bothwick <n...@digimed.co.uk> > > > > > > > > On Thu, 07 Apr 2011 05:22:41 -0500, Dale wrote: > > > > > I want to do it this way because I don't trust LVM enough > > > > > to put my > > > > > > > > > > OS > > > > > on. Just my personal opinion on LVM. > > > > > > > > This doesn't make sense. Your OS can be reinstalled in an hour > > > > or two, your photos etc. are irreplaceable. > > > > > > Makes perfect sense to me as well. > > > > > > Having installed LVM - and then removed it due to issues; namely, > > > the fact that one of the hard drives died taking out the whole LVM > > > group, leaving the OS unbootable, and not easily fixable. There > > > was a thread on that (started by me) a while back (over a year). > > > > > > So, perhaps if I had a RAID to underly so I could mirror drives > > > under LVM > > > > > > for recovery I'd move to it again. But otherwise it is just a PITA > > > waiting > > > > > > to happen. > > > > > > Ben > > > > Unfortunately, any method that spreads a filesystem over multiple disks > > can be > > > > affected if one of those disks dies unless there is some mechanism in > > place that can handle the loss of a disk. > > For that, RAID (with the exception of striping, eg. RAID-0) provides > > that. > > > > Just out of curiousity, as I never had the need to look into this, I > > think that, in theory, it should be possible to recover data from LVs > > that were not > > > > using the failed drive. Is this assumption correct or wrong? > > If you have the LV configuration information, then yes. Since I managed to > find the configuration information, I was able to remove the affected PVs > from the VG, and get it back up. > I might still have it running, but I'll back it out on the next rebuild - or > if I have a drive large enough to do so with in the future. I was wanting > to use LVM as a bit of a software RAID, but never quite got > that far in the configuration before it failed. It does do a good job at > what it's designed for, but I would not trust the OS to it either since the > LVM configuration is very important to keep around. > > If not, good luck as far as I can tell. > > Ben
LVM isn't actually RAID. Not in the sense that one gets redundancy. If you consider it to be a flexible partitioning method, that can span multiple disks, then yes. But when spanning multiple disks, it will simply act like JBOD or RAID0. Neither protects someone from a single disk failure. On critical systems, I tend to use: DISK <-> RAID <-> LVM <-> Filesystem The disks are as reliable as Google says they are. They fail or they don't. RAID protects against single disk-failure LVM makes the partitioning flexible Filesystems are picked depending on what I use the partition for -- Joost
