[Gluster-devel] Gluster Recovery

[Krishna Srinivas]

Hi Danson,

Answer inline..

On 4/23/07, Danson Michael Joseph <danson.joseph at baobabelectric.com> wrote:
> Hi,
>
> I recently compiled and tested Gluster 1.3 on Ubuntu 7.04 and all went well.
> Originally I intended to use DRBD in our small cluster of 2 machines but
> couldn't get the module to compile.  The feature needed in DRBD is really the
> self-recovery after failure.  SO after choosing gluster, I'm looking for
> answers to two operational questions:
>
> 1) If DRBD rolls over from slave to primary and then the primary goes online
> again, the original primary will become slave and copy/resync with the old
> slave which is now primary.  In gluster is this as simple as using a rsync
> script to achieve the same?

In glusterfs, as of now resync can be done using rsync. In future we will
have automated builtin facility in glusterfs to do this.

>
> 2) Lustre uses metadata on two or distributed MetaData Servers.  I presume this
> means that if a storage node fails and I go out and buy a new machine and plug
> it in, the MDS server will re-populate the new server with what was on the old
> server, based on it's MDS knowledge and the replicated data on other servers.
> If gluster has no MDS, how can replication take place?  There seems to be know
> "knowledge" of the system like a MDS server has?

We do not need metadata information to resync. For example, if we are doing
AFR on 2 nodes and we replace one of the nodes, the recovery module will
get to know that one of them is new, so it will copy all the files and
directories
to this new server. We need to see what all cases we need to handle,
this feature
is in our road map.

Regards
Krishna

>
> Regards,
>
> --
> *********************************
> Danson Michael Joseph
> danson.joseph at baobabelectric.com
> PO BOX 1768, BEDFORDVIEW, 2008, SOUTH AFRICA
> +27 82 820 4261
>
>
>
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