Large volumes

[David J. M. Karlsen]

Craig_Everhart at transarc.com wrote:

>Excerpts from transarc.external.arla-drinkers: 10-Dec-01 Large volumes
>David J. M. Karlsen at davi (944)
>
>>Does [Open]AFS only sync complete volumes? Say I changed (eg. added) a
>>2MB file to the volume /afs/myvol - and the myvol was 8GB - would AFS
>>try to sync the entire 8GB - and not only the diff? Does arla support
>>larger volsizes? 
>>
>
>The volume limit in AFS is pretty much advisory, even the 8GB one.  But
>it takes a long time to move or backup or replicate big volumes.  I
>
No problem - the volume will stick in the same place all the time. (eg. 
/afs/users - no quota stuff - and there's a lot of data pr. "user"). 
Backup takes long time anyway - the same amount of data - and I'll be 
able to run a full backup in just abount 24hrs :-))
Will replication be a problem? Let's say I had three diffrent volumes 
/afs/{a,b,c} - to a total amount of 120GB. We'll assume a daily change 
rate on abount 10GB on each volume
, totalling to a 30GB/24hrs. Would this be quicker than a 30GB change on 
a 120GB volume?

both setups: two servers -> one master and a replica.

And if it's faster - why?

>
>don't know what you mean by "sync" a volume.  If you replicate a big
>
that the replica has catched up - and both servers sit on the same data.

>volume and then add a 2MB file to it and then replicate again, just the
>new file (and the parent directory) are copied across.  But moving the
>big volume (from one place to another) still has to copy all the data.
>
that's why I want to go for one big volume: /afs/data

>Sorry, but I don't know the Arla limits.
>
I first wanted CODA - but it has it's limits too - then i wanted to go 
for OpenAFS - therefore these questions :)
My last chances are: OpenGFS (really for more sophisticated hardware - 
and too fresh prerel. alpha) or
NBD-raid (doomed to die! :-))