reducing beegfs volume/removing a storage node?

[Tru Huynh]

Hello,

Is there a way to reduce the beegfs volume once it is in use?

Or the best pratice would be to use the BeeGFS on demand ?

In case of a scheduled maintenance of a storage node, can we force
beegfs to rebalance the data from that storage node onto the remaining
ones?

Best regards

Tru
--
Dr Tru Huynh | http://www.pasteur.fr/research/bis
mailto:t...@pasteur.fr | tel/fax +33 1 45 68 87 37/19
Institut Pasteur, 25-28 rue du Docteur Roux, 75724 Paris CEDEX 15 France

[Bogdan Costescu]

Hi Tru,

you might find some answers in the following 2 FAQ entries:

http://www.beegfs.com/wiki/FAQ#remove_node
http://www.beegfs.com/wiki/FAQ#migrate

If you know what files (as seen from a mounted BeeGFS filesystem) are
located on that storage server, I think that you can achieve a similar
result by manually setting the pool for the storage server such that
new data is not stored on it, then simply 'mv' to a new directory on
the same filesystem.

Cheers,
Bogdan

[Tru Huynh]

Hi Bodgan,

On Thu, Feb 18, 2016 at 08:47:14AM +0100, Bogdan Costescu wrote:
> Hi Tru,
>
> you might find some answers in the following 2 FAQ entries:
>
> http://www.beegfs.com/wiki/FAQ#remove_node
> http://www.beegfs.com/wiki/FAQ#migrate

No idea, how I managed to miss these entries for shrinking the beegfs
filesystem.

Any idea of what happen if I remove the node, before migrating the data out?
Or marking the node for removal is just preventing any further write access?

$ beegfs-ctl --migrate --help
...
If new files are created by applications while migration is in progress, it
is possible that these files are created on the target which you want to free
up. Thus, be careful regarding how you access the file system during migration.

So there is no way to tell beegfs not to use the node targeted for removal?

>
> If you know what files (as seen from a mounted BeeGFS filesystem) are
> located on that storage server, I think that you can achieve a similar
> result by manually setting the pool for the storage server such that
> new data is not stored on it, then simply 'mv' to a new directory on
> the same filesystem.

I am not familiar enough with beegfs, how do you:
- map files <-> storage nodes?
- mark a storage node to no longer accept more write?

Thanks :P

Tru

[Tru Huynh]

On Thu, Feb 18, 2016 at 09:20:59AM +0100, Tru Huynh wrote:
...

> - mark a storage node to no longer accept more write?

that was answered in the other thread :P

http://www.beegfs.com/release/fhgfs_2012.10/Changelog.txt

* storage/meta: New method to manually override reported amount of free disk
space through a "free_space.override" file in a target directory. This can be
used e.g. to report 0 disk space left for a certain target, so that it gets
moved to the emergency pool and thus won't be used for new files:
$ echo 0 > <storeStorageDirectory>/free_space.override
(No daemon restart is required when the file is created or removed.)
[Thanks to Megware for suggestion during user meeting 2013.]

Cheers