[Discuss] Backing up LVM partitions using snapshots

[Richard Pieri]

On 12/13/2011 12:01 PM, Derek Martin wrote:
 > You run fsck.

That won't work.  fsck fixes errors in metadata but there are no errors 
in the directory metadata.  It's a perfectly valid-looking directory 
entry as far as fsck is concerned.  It isn't a valid file from the 
owner's perspective since the inode list points to empty blocks -- or 
who knows what on a "dirty" volume.  Which brings up a serious security 
concern: cross-linked file data on dirty volumes.  You have no control 
over which blocks get assigned to a volume on creation, and some of 
those are going to be reused.  You could scrub everything on volume 
deletion, but that's going to kill SSDs (we had that discussion earlier 
this year).

This is a non-issue with file-level backups.