[COLUG] drbd ?

[Mike Warfe]

It is possible to do a primary/primary using a clustered file system 
like GFS2 or OCFS2 with the 0.8 DRBD code. I haven't tried this myself 
but can see it as a viable way to build out the storage infrastructure 
for a Xen cluster. I think you need to look at the application to see 
when it is necessary to do primary/primary. For my implementation, when 
I implemented this over a year ago the primary/primary code was not 
ready for production yet. Personally though, I prefer to stick with the 
primary/secondary setup due to my lack of confidence in running Vmware 
server in such an environment.

For MySQL it may be wise to look at the MySQL cluster stuff 
http://www.mysql.org/doc/refman/5.0/en/mysql-cluster.html. You could put 
a MySQL cluster behind a LVS router and have it actively monitor each 
node to ensure uptime. This would also allow you to scale MySQL which 
could help performance.

-Mike

> Rob Funk wrote:
> Possibly dumb questions from someone whose high-availability experience to 
> date stops at RAID....
>
> With drbd, why not do primary/primary rather than primary/secondary?
>
> In general, why not (or: is it possible to) have both machines normally 
> doing a share of the work, rather than one being idle until the other 
> fails?
>
> -- 
> ==============================|   "A microscope locked in on one point
>  Rob Funk <rfunk at funknet.net <http://www.colug.net/mailman/listinfo/colug432>> |Never sees what kind of room that it's in"
>  http://www.funknet.net/rfunk |    -- Chris Mars, "Stuck in Rewind"
> Mike Warfe wrote:
> I've got it running on two Centos4 machines in a master/slave 
> configuration. The cluster runs vmware server and I use heartbeat to 
> do the automatic fail over between the two hosts. The hardest part of 
> getting this to work was getting vmware to not choke when the fail 
> over machine mounts the replicated partitions. The heartbeat service 
> and drbd can be found in the Centos plus repo. I believe.
> --Mike
>
> Anyone using drbd ?
>
> Distributed replicated block device ?
>
> I am curious about it.
>
> I do not know what my schedule is but if there is someone in COLUG  
> who uses DRBD and would like to present then I would try to attend.
>
> If there is no one who is using it I guess I could learn on my own  
> and share what I learn.
>
> Anyone familiar with drbd or other similar tools ?
>
> -- 
> Tom
>
>
>