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Re: fs block level syncing



Paul Raines <raines nmr mgh harvard edu> wrote:

Hello.

> Right now we do a lot of hard to hard disk backup by using rsync to weekly
> "mirror" the source filesystem to a backup filesystem. This works fairly
> well for most sources.  However, one issue with rsync is that simple things
> like changing the file name or directory name cause the whole file or
> directory structure to get recopied over a previous sync. Also, like for
> mail spools, large files that simply get appended to get the whole file
> recopied.
>
> Does anyone know of something that syncs an ext2/3 fs to another
> at the block level which result in less data transfer?

No.

If you are able to use UML, you could copy the whole block device once 
(creating an image on the backup side), than start the system in an UML 
session on the source side, using a cow (copy on write) file, and copy 
that cow file on a daily (weekly/monthly) base. After each backup merge 
that cow file on the source and on the backup side to the full image 
(and start a new cow file on the source side). Theoretically the same 
concept could be achived w/o using UML, but that would need some kernel 
hacking ;-)

But I don't know of any user-space solution for that.

Regards, Bodo
-- 
No, there is no program running called explorer.exe.




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