[Gluster-users] replica count documentation

[Burnash, James]

Actually, my understanding is that the replica count actually refers to how many bricks each file will be replicated to. The distinction is that if you have multiple bricks on a single server, you can create the volume in such a way that all replication is done within that single server.

In order to make sure that replication happens ACROSS servers, you must make sure that the bricks defined in the gluster create volume stanza look like this:

Gluster volume create replicate 2 <server1>:/brick1 <server2>:/brick1 <server1>:/brick2 <server2>:/brick2 etc ...

This construction will mirror each brick onto the other server, allowing complete failure of either server while still keeping the volume up. It's also handy for upgrading each server in turn without a service disruption.

The documentation is not specifically explicit about this scenario and its implications ... or wasn't, last time I looked.

James Burnash, Unix Engineering

-----Original Message-----
From: gluster-users-bounces at gluster.org [mailto:gluster-users-bounces at gluster.org] On Behalf Of Mohit Anchlia
Sent: Wednesday, April 13, 2011 7:18 PM
To: Craig Younkins; gluster-users at gluster.org
Subject: Re: [Gluster-users] replica count documentation

My understanding is that the file you are writing to is replicated
accross "n" number of glusterfs servers. You define that "n" when
creating volume.

Try volume info command to see the replicas.

On Wed, Apr 13, 2011 at 4:14 PM, Craig Younkins <cyounkins at gmail.com> wrote:
> So these are probably dumb questions but I cannot find them anywhere in the
> documentation.
>
> What exactly does the replica count paramater to the volume create command
> mean? How many bricks each block is replicated to?
>
> How does one query for the replica count of a volume?
>
> Thanks!
>
> Craig Younkins
>
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