[KLUG Members] Server Mirroring

[Jamie McCarthy]

adam at morrison-ind.com (Adam Tauno Williams) writes:

> > My final goal is to have a fault tolerant solution with a
> > database. Have the database mirrored to two server. Use
> > HeartBeat to fail over the actual database server application
> > if one fails.
> 
> If by "database" you mean an RDBMS (SQL database engine):

I think he does :)

> > Anyone know if any such mirroring software?
>
> No. ***Reliably*** and ***consistently*** replicating an RDBMS
> is really really really really really H-A-R-D.  If you
> absolutely need this as a hot-pair.... buy DB2.

MySQL does this.  Clusters have been powering most of LiveJournal's
writer DBs for months now.  Clustering has been available through
third-parties for a while, but don't bother with that, since it's
part of the core software now, in MySQL 4.1:

http://dev.mysql.com/doc/mysql/en/NDBCluster.html

Adam's right that it's hard to set up.  But I don't know if it's
five really's worth of hard.  I'm planning on doing this for
Slashdot sometime in the next year and I'm kind of a dumbass.
-- 
  Jamie McCarthy
 http://mccarthy.vg/
  jamie at mccarthy.vg