Re: data replication how to

[Ioannou Ioannis <iik1@hellespont.com>]

On Thursday 29 July 2004 19:09, Yohann Desquerre wrote:
>
> i think i would plug the 2 storage product and the debian  into the
> switch and then use unison to replicate the data (or do a snapshot)...

unison is good for bidirectional replication (i.e. changes are happening in 
both storage devices).
The other alternative (for unidirectional replication only) is rsync.
The speed depends on the size (and the H/W). Sometime rsync is faster, but I 
think in your case unison may be better, it is amazing how fast it can check 
huge directories for changes.

But mind also that unison has a problem with huge directories and zillions of
files the first time (until the initial database is created). You have to do 
the replication part by part at least once, and the everything is ok. What I 
had to do in a similar situation was to use something like :

root=/path/to/first/root
root=/path/to/second/root

path=firstDir
# path=secondDir
# path=thirdDir
# path=fourthDir

etc, and sync segment by segment (each somethingDir small enough so that 
unison had no memory problems).
As soon the database is created and unison went through of all the files at 
least once, you could trust it to do the job fast (depending of the H/W 
setup, maybe faster than your time contrains)


-- 
Rgrds
iik1