[CentOS] Re: Keeping data on 2 servers in sync !

[rado]

On Mon, 2005-12-05 at 21:21 -0500, Chris Mauritz wrote:
> Johnny Hughes wrote:
> 
> >On Mon, 2005-12-05 at 15:44 -0800, Bryan J. Smith wrote:
> >  
> >
> >>Ugo Bellavance <ugob at camo-route.com> wrote:
> >>    
> >>
> >>>I'd take a look at drbd (www.drbd.org) while you're reading
> >>>on heartbeat.  I use it for web servers, but I'm not sure
> >>>if it would be suitable for file servers.
> >>>      
> >>>
> >>There is a lot more to handling network file services --
> >>especially when it comes to locking and controlling write
> >>access -- that web servers don't have to worry about.  ;->
> >>
> >>    
> >>
> >I use drbd and heartbeat on a samba domain controller that has
> >failover ... BUT, you can't use both machines at the same time.
> >
> >AND, it takes a GiB connector to keep the files in sync ... trying to do
> >it via a WAN connection would, I think, be fairly impossible.
> >  
> >
> 
> I've managed to keep two moderately busy servers in sync using frequent 
> rsync over a WAN VPN tunnel.  However, that tunnel was over an OC-3 
> link.  I suspect it would be a rather painful affair over DSL/cablemodem 
> or even a few bonded T1's.  Something like drbd that treats a remote 
> volume as a device would definitely not work on such a "skinny" link 
> unless the servers were relatively lightly used.
> 
> Cheers,
I sync up 2 servers w/software I wrote myself but I only use this along
the lines of "HA" techniques.
also...not real time...that would be ummm...pretty high dollar stuff
there...I sync up bout every 20-30 seconds
Both servers are not running at the same time. It's a master/slave deal
w/the slave just constantly checking on the master...it the slave deems
the master is in trouble...it just takes the ip and it's the master
until you intervene.

depending on what you want to sync up... it might work...the key w/this
is that only 1 server is serving at any given time.

john rose