LVM and NFS mounts

[Matthew Gillen]

David Rosenstrauch wrote:
> Getting off the topic of LVM+NFS a bit here, but I've heard that a setup 
> like that (i.e., a logical volume that spans multiple physical drives) 
> can actually get you into trouble.  I can't recall the exact specifics, 
> but the gist was that if one of the physical drives dies or gets 
> corrupted, LVM can get pretty hosed trying to serve up the data on the 
> LV.  Old wives' tale?

No, that's not a old wives' tale.  Using multiple disks (in a non-RAID
configuration) for a single logical volume increases your chance of volume
failure.  A large amount of traffic on the LVM list used to be dedicated to
people losing one disk out of a volume and wanting to salvage whatever
happened to be on the still-good disk.

Personally, I don't use LVM to create really huge filesystems (ie spanning
multiple disks) because I care about my data.  I use multiple disks to create
a RAID-1 array, then use the RAID array as the physical device for the LVM.

Gives the flexibility at the filesystem level of LVM, while keeping the
benefits of RAID.

Matt