[Gluster-devel] Splitbrain Resolution

[Samuel Douglas]

On Sat, Apr 19, 2008 at 5:54 AM, Reinis Rozitis <r at roze.lv> wrote:
>  That way the afr-copying is done on the "server" level..
>
>  Only drawback in this is your clients can mount only one server so if one
> goes down you have to remount or implement some other HA method (like dns or
> heartbeats)).

This is a fairly serious drawback, but it depends what you want AFR
for. In our cluster system, we are probably using AFR with two
children to provide file replication; until the HA translator is
available, these are loaded on the client.

As Gordan said, yes, the bandwidth does increase n-fold, but only for
writes; and if you have gigabit ethernet and a decent switch this
should not be too much of a problem. The data still has to go to all
the replicated servers, so it is just the client's interconnect that
has higher utilisation. Unless your workload is very heavy on writes,
this shouldn't be a major problem.

You can also use write-behind to aggregate writes, which can help
avoid unnecessary overheads caused by making many small writes to the
AFR volumes.

-- Samuel