[Gluster-users] deployment

[Harald Stürzebecher]

Hello!

2008/9/17 Raghavendra G <raghavendra.hg at gmail.com>
>
> Paolo,
> Comments are inlined.
>
> On Wed, Sep 17, 2008 at 3:25 PM, Paolo Supino <paolo.supino at gmail.com> wrote:
>>
>> Hi Keith
>>
>>   There's a section on the website that gives the configuration for a unify/AFR but doesn't say whether AFR goes above or below unify. At the moment I don't need the whole 2TB and I can live with half of it, but I might down the road need the extra space. If and when that happens is it possible to break the unify/AFR and move everything to only unify without deleting data (not that will be an obstacle, see below)?
>
> Its recommended while adding new children to unify, the back end filesystems of children to be empty, hence you've to delete the data.

It would be nice to be able to restructure the storage safely without
deleting the data, that might be a big argument for using GlusterFS
instead of other storage solutions.

I think it is possible to create a new GlusterFS structure in
different directories on the same underlying filesysstem(s), export
both the old and new volumes, mount both of them and move the data
from the old GlusterFS mount to the new one without loosing data.
After moving all the data the old volumes could be removed from the
configuration.
As long as there is free space to move (=copy+delete as the source and
destination files are on different mountpoints) the biggest file on
the volume I would not expect any problems. The space needed for the
new volume would be freed when the files are moved from the old
volume. It might take some time to move all the files...

Could this be done?

I think the requirements for this "operation" would be:
- One server can export multiple volumes - the one with the existing
data and one for the new setup. =>
http://www.gluster.org/docs/index.php/Aggregating_Three_Storage_Servers_with_Unify
shows this with the data and namespace volume. IMHO, exporting more
volumes should not be a problem.
- One client can mount two server volumes on two different mountpoints
=> Could not find any documentation on that but I could not find
anything that says that cannot be done at least with two different
client volume spec files.
- Some Volume Spec files for the servers and clients containing both
the old and the new configuration.


Harald Stürzebecher