[Gluster-devel] Brick path used for gluster shared storage volume

[Avra Sengupta]

On 07/05/2015 02:24 PM, Niels de Vos wrote:
> On Sun, Jul 05, 2015 at 10:16:06AM +0530, Avra Sengupta wrote:
>> Hi,
>>
>> Today with with enabling volume set option cluster.enable-shared-storage, we
>> create a shared storage volume called gluster_shared_storage for the user,
>> and mount it on all the nodes in the cluster. Currently this volume is used
>> for features like nfs-ganesha, snapshot scheduler and geo-replication to
>> save some internal data required by these features. The brick path we use to
>> create this shared storage is /var/run/gluster/ss_brick.
>>
>> The problem with using this brick path is /var/run/gluster is a tmpfs and
>> all the brick/shared storage data will be wiped off when the node restarts.
>> Hence I propose using /var/lib/glusterd/ss_brick as the brick path for
>> shared storage volume as this brick and the shared storage volume is
>> internally created by us (albeit on user's request), and contains only
>> internal state data and no user data.
> /var/run/ is not a tmpfs on EL6 and before, but it is cleaned out on
> boot. /var/run/ or /run/ on recent Fedora and EL7 is really only valid
> for the current boot.
>
>> We are also aware that admins sometime take backup of /var/lib/glusterd to
>> save the current state of gluster. Again this shouldn't be an issue as the
>> data contained in these bricks is only internal state data and is very
>> minimal.
>>
>> Please let me know if there are any issues or concerns with using
>> /var/lib/glusterd/ss_brick as the brick path for the shared storage, and
>> also suggest an alternate brick path.
> Yes, /var/lib/glusterd/ss_brick/ is much more suitable. Please check
> what is a common path for NetBSD and others, I think they use /var/db/
> for these kind of things. The already used #defines and autoconf/make
> variables should just apply.
I think as u mentioned in the upstream patch for 
this(http://review.gluster.org/#/c/11533/), using GLUSTERD_WORKDIR 
should take care of NetBSD too...
>
> If the shared volume gets mounted, (/var)/run/gluster/state/ is
> suitable. There is no need to have the glusterfs-fuse mountpoint under
> /var/lib/, (/var)/run/ is more appropriate.
We don't mount the shared volume under /var/lib. It's just the brick. 
The shared vol will be mounted under /var/run/gluster/shared_storage.
>
> Thanks,
> Niels