Re: [Xen-users] Xen backups using LVM Snapshots

[John Haxby <john.haxby@xxxxxxxxxx>]

Kevin Fox wrote:
> If there is such a connection between the LVM snapshotter and the file
> system, I could see it not working properly if the LVM snapshotter is in
> dom0 and the file system in domU. Perhaps a xen extension could be added
> to support that?
>   
There is indeed such a connection within the same OS and yes, if you 
want to take a back up of the guest's file system you need to enlist its 
cooperation to get the file system into a consistent state before you 
take the snapshot and, of course, to let it go afterwards.   In general, 
you'll also need the cooperation of any applications that are running as 
well.
In the end, though you have to ask yourself if it's worth it.   For 
example, someone, somewhere mentioned running mysqlhotbackup in the 
guest and putting the files somewhere that dom0 could see them.   Is it 
quicker, in the end, to recover the OS data from a backup or just run a 
kickstart installation to rebuild it?   Chances are that if you're 
backing up an entire system by, basically, photocopying the disk, you're 
backing up a load of stuff you don't need to.
There are hardware configurations where dom0 driven backups are better, 
but to make them as good as bare-metal backups then you really need the 
cooperation and, in many cases, active help from the domU.
jch

_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users