Re: [Xen-users] snapshot backup at iscsi or dom0, which one is better?

[Simon Hobson <linux@xxxxxxxxxxxxxxxx>]

Aclhk Aclhk wrote:
> dom0 mounts disk from iscsi server lvm. domU mounts dom0 lvm.
>
> pls kindly advise which one is better.
Neither can give you a clean backup - period. But beyond that, both 
will achieve the same effect - an image of a dirty disk that will 
need to be restored in it's entirety even if you only need on file 
from the backup.
Either way will give you an image of a dirty disk partition, missing 
anything in the guests cache waiting to be written. And that's also 
ignoring applications (particularly databases) that have dirty data 
in their own cache.
In short - imagine pulling the power cord. You backup will be the 
equivalent of what's on the disk at the point you kill the power.
If you want a usable and clean backup - do it from within the guest 
(so it will include any dirty cache) and don't forget applications 
like databases that typically have to be shut down, put into some 
sort of backup mode, or perform a data dump in order to get a clean 
backup.
--
Simon Hobson

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.

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