Re: [Xen-users] A simple backup

["Fajar A. Nugraha" <fajar@xxxxxxxxx>]

Mark Williamson wrote:
> When you take an atomic snapshot of a domU's state, it's much the same kind of 
> backup image as you'd get by yanking the power from a server, removing its 
> hard drive and copying it byte-for-byte - often readable but definitely not 
> clean.  That consistency problem is what makes it impossible to guarantee 
> that such backups are definitely readable.
>   
Hi Mark,

Some thoughts about your comment.
In our environment, one of the requirements for the OS and applications 
is that it must be able to recover quickly and cleanly from a power 
failure. This is actually one of the reasons why we're starting to 
migrate some stuff to zfs : because, when used properly, it always 
guarantee filesystem consistency in the event of power failure.
IMHO, even the best commercial SAN-based backup solution uses that 
assumption, so for practical purposes, atomic backup for domU's storage 
should be sufficient.
> It would be nicer if you could somehow guarantee a 
> consistent filesystem state on your disk snapshot.  I've been looking into 
> how to do this and I believe it's quite possible to modify the code to 
> support this properly.
>   
It would be interesting if you can make it happen.

Regards,

Fajar

Attachment: smime.p7s
Description: S/MIME Cryptographic Signature

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