Re: cluster de serveurs web+mail

Et pour le cluster, j'ai recu un email d'un gars tranquille. Pas du tout eu le temps de tester mais je pense que ca marchera sans trop de pb

Hi Sylvestre,

I didn't want to reply until I'd got it working and knew what needed to
be done.

I'm using LVS (http://www.linuxvirtualserver.org/(...)) to distribute the
load between the two mail servers. The mail servers are using a shared
NFS file system for /home/vpopmail /var/qmail/control /var/qmail/alias
and /var/qmail/users.

This works great for clustering all of the mail services - smtp, pop,
webmail, and imap.

The only problem is if the shared NFS server has a problem because
obviously this is a single point of failure. Firstly it's a NAS so very
reliable but just in case, I also sync the NFS directories every few
minutes to local folders on the mail servers. This way if the NAS has a
problem, I can redirect the mail servers to use a local store (one
accessing the local store on the other mail server via NFS again). This
isn't great because there is the potential for lost mails unless I stop
qmail delivering mails, sync the NAS and then switch qmail to use the
local store first. However the cluster was designed for failure of a
mail server and not the NAS and this is just an extra level of
redundancy in case the worst happens.

Thanks,

Matt.
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Matthew Francis