[CentOS] Rsync and differential Backups

[Gordon Messmer]

On 11/13/2015 01:46 AM, J Martin Rushton wrote:
> If you really_need_  the guarantee of a snapshot, consider either LVM
> or RAID1. Break out a volume from the RAID set, back it up, then
> rebuild.

FFS, don't do the latter.  LVM is the standard filesystem backing for 
Red Hat and CentOS systems, and fully supports consistent snapshots 
without doing half-ass shit like breaking a RAID volume.

Breaking a RAID volume doesn't make filesystems consistent, so when you 
try to mount it, you might have a corrupt filesystem, or corrupt data.  
Breaking the RAID will duplicate UUIDs of filesystems and the name of 
volume groups.  There are a whole bunch of configurations where it just 
won't work.  At best, it's unreliable.  Never do this.  Don't advise 
other people to do it.  Use LVM snapshots (or ZFS if that's an option 
for you).