continuous backup solution for FreeBSD

[Evren Yurtesen]

Zaphod Beeblebrox wrote:
> On Wed, Oct 8, 2008 at 4:14 AM, Dag-Erling Smørgrav <des at des.no 
> <mailto:des at des.no>> wrote:
> 
>     "Zaphod Beeblebrox" <zbeeble at gmail.com <mailto:zbeeble at gmail.com>>
>     writes:
>      > "Dag-Erling Smørgrav" <des at des.no <mailto:des at des.no>> writes:
>      > > What really annoys me with this thread is that nobody has provided
>      > > any information at all that would allow someone to understand what
>      > > needs to be done and estimate how hard it would be.
>      > Well... I hinted that a hammer port would be sufficient (although
>     they
>      > need to finish their replication design) and I hinted that the hammer
>      > approach may be graftable to ZFS.  Both reasonably large effort-wise
>      > (but probably within the scope of a single developer with sufficient
>      > time).
> 
>     No...  you're so far off the mark it's not even funny, especially when
>     it's been repeatedly pointed out to you.  This is not a file system,
>     it's a backup system.  It's not designed to survive a disk crash or an
>     accidental file deletion, it's designed to survive a direct missile
>     strike on your colo center.
> 
>     To quote Wikipedia, "CDP is a service that captures changes to data to a
>     separate storage location" - emphasis on "separate".
> 
> 
> Wow... thanks for the flame, but there's no reason that the  device that 
> is receiving the hammer replication couldn't be on the other side of the 
> globe and there's no reason it couldn't be considered a backup.  Part of 
> the advantage of the structure that allows you to efficiently select for 
> new changes allows you to do the same kind of *backup* as they claim.
> 

Wouldnt that device need to keep the whole filesystem? Like if you have 
10 machines with 10x 1GB drives (lets say each used about 250gb), you 
will need 10TB disk space in the backup server?