[Box Backup] Two backup-servers

[Chris Wilson]

Hi Jeroen,

On Wed, 30 Jan 2008, Jeroen van Pelt / Skool Automatisering wrote:

> Currently we are researching the possibility to use DRBD to keep to
> servers in sync. At the moment we are using DRBD to keep a set of two
> iSCSI servers in sync. This works wonderfully; we can take down either
> server without the Vmware guests running from it on separate Vmware
> hosts being interrupted. Automatic resync makes maintenance a breeze.

High or low bandwidth between the iSCSI server sets?

> What we are thinking about doing for our BoxBackup setup (we have two
> completely separate setups/servers right now), is to set up two servers
> with lots of disk space syncing a resource with DRBD. Then we would
> serve this syncing resource through iSCSI to two separate "front end"
> BoxBackup servers that we would make HA through something like
> heartbeat.
> 
> This way you have data redundancy (between the two DRBD boxes) and HA
> through your front-end server. I'd imagine one would be able to this
> also with just two server acting as front-end and storage at the same
> time.
> 
> Does anyone see any caveats?

You can't mount the same block-based filesystem using iSCSI (even via 
different iSCSI servers) on two Box Backup servers at the same time unless 
you use a really weird filesystem like GFS?

Serving NFS instead of iSCSI might do it.

Cheers, Chris.
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