[Techtalk] The Ark

[Conor Daly]

I'd be inclined to say NFS is a pretty reasonable route.  there's one
caveat though; nfs will take forever to timeout if a machine is not
available.  f'rinstance, at home I had nfs mounted some mp3s from another
box, took that box into work and the box at home took 20 minutes to time
out when booting 'cos it was trying to mount the nfs volume that wasn't
there.  For that reason, I'd export the server's disk and nfs mount it on
the clients rather than the other way around.  That way, when someone
shuts down their machine, locks their office and goes away for a months
holiday, the server won't keep hanging trying to access their disc.
(Geez, sometimes I'm eloquent...   sometimes not!)

Each machine can have a cron job to run "dump -n" where n os the level of
the backup (0=full, 1-9= differing levels of incremental) (man dump gives
a nice order of backup levels based on minimising the number of different
backup volumes needed for a complete restore).  The dump should just
generate a file on the nfs mounted "Ark" disk and all is happy.

Of course, this completely eliminates the possibility of having the entire
process controlled by the Ark since the clients need to push to the server
while an Ark-based setup would require the server to pull from the clients
but you then have the nfs timeout problem.  You could do something like
the following on the Ark;

1. ping client_1
2. if response then nfs mount client_1
3. do backup of client_1
4. umount client_1
5. ping client_2
6. if response then nfs mount client_2
7. do backup of client_2
8. umount client_2
9. repeat ad nauseam...

and so on.  Thus, the server checks to see if client_x is up before it
tries to mount its disk and unmounts it immediatly after the backup thus
avoiding the problem of trying to mount a down machine.

Conor
On Sat, Feb 23, 2002 at 07:14:04PM -0500 or so it is rumoured hereabouts, 
James thought:
> Hiya all.
> 
> We have several web/SQL servers on our network.  
> 
> What would be the easiest to create a system which would allow us to
> regularly backup and save the backup to another server? (I'll call the
> NFS server "The Ark"*)
> 
> I was thinking NFS for it, but I was unsure of how to do it (in terms of
> architecture).  
> 
> Should "The Ark" setup such that it mounts a drive on each server and
> then copies the information from the remote drive to its own?  Or should
> the remote copy to the The Ark?
> 
> Or should the web/SQL servers mount a drive on "The Ark" and copy their
> stuff to "The Ark"?  Or should they a;; mount a drive on "The Ark" and
> have "The Ark" copy stuff off?
> 
> (Basically it is a decision of who should mount or who and who should do
> the push/pull.  Omg I just realized how misconstrued that sentence could
> be).
> 
> Right now I'm actually tar+gzing the stuff myself and copying it to my
> home computer, then burning it to CD.
> 
> - James
> 
> * Because we have the only server room in North America where flooding
> is sometimes an issue :)  The backups aren't because of this, it is just
> an inside joke and I think I find it a good classical reference :)
> 
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-- 
Conor Daly <conor.daly at oceanfree.net>

Domestic Sysadmin :-)
---------------------
Faenor.cod.ie
  8:10pm  up 39 days,  9:38,  0 users,  load average: 0.00, 0.00, 0.00
Hobbiton.cod.ie
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