[Gluster-users] Is mirroring provides failover protection?

[Rudi Ahlers]

On Wed, Jan 19, 2011 at 12:10 PM, Andrew Séguin <aseguo at gmail.com> wrote:
> Hi,
>
> Assuming the replication works fine (you see the files on both servers
> A and B) and that you use the Gluster client (mount -t glusterfs ...),
> then if server A goes down, your application will continue seamlessly
> to use server B although you could encounter problems later:
>
> If the server with your application has to restart, and server A is
> down at that moment, then unfortunately the gluster client does not
> connect to a gluster server, and does not get to know that server B
> exists.
>
> To avoid that problem, you can prepare your Gluster cluster system
> with 3 IP addresses: server A, server B, and a "shared" IP for the two
> nodes which will be active only on one of the two servers at a time.
> Some system then has to decide which server is currently master -- the
> CARP protocol could be of help here. Maybe the following blog/howto
> would be of help for this:
> http://www.misdivision.com/blog/setting-up-a-highly-available-storage-cluster-using-glusterfs-and-ucarp
>
> With NFS & CIFS the clients don't know about the second server, in
> case you do not have a shared IP, the connection would be broken. NFS
> without the shared IP is the same as having an offline backup but with
> the advantage that the backup is up to date.
>
> While I'm not a gluster expert, I hope this helps!
> Andrew
>
>

At this stage you need to use pNFS (parallel NFS) to make NFS more redundant :)




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Kind Regards
Rudi Ahlers
SoftDux

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