On Tue, May 2, 2017 at 12:07 AM, Shyam <srangana at redhat.com> wrote:
> On 05/01/2017 02:23 PM, Pranith Kumar Karampuri wrote:
>
>>
>>
>> On Mon, May 1, 2017 at 11:43 PM, Shyam <srangana at redhat.com
>> <mailto:srangana at redhat.com>> wrote:
>>
>> On 05/01/2017 02:00 PM, Pranith Kumar Karampuri wrote:
>>
>> Splitting the bricks need not be a post factum decision, we
>> can
>> start with larger brick counts, on a given node/disk count,
>> and
>> hence spread these bricks to newer nodes/bricks as they are
>> added.
>>
>>
>> Let's say we have 1 disk, we format it with say XFS and
that
>> becomes a
>> brick at the moment. Just curious, what will be the
relationship
>> between
>> brick to disk in this case(If we leave out LVM for this
example)?
>>
>>
>> I would assume the relation is brick to provided FS directory (not
>> brick to disk, we do not control that at the moment, other than
>> providing best practices around the same).
>>
>>
>> Hmmm... as per my understanding, if we do this then 'df' I
guess will
>> report wrong values? available-size/free-size etc will be counted more
>> than once?
>>
>
> This is true even today, if anyone uses 2 bricks from the same mount.
>
That is the reason why documentation is the way it is as far as I can
remember.
>
> I forgot a converse though, we could take a disk and partition it (LVM
> thinp volumes) and use each of those partitions as bricks, avoiding the
> problem of df double counting. Further thinp will help us expand available
> space to other bricks on the same disk, as we destroy older bricks or
> create new ones to accommodate the moving pieces (needs more careful
> thought though, but for sure is a nightmare without thinp).
>
> I am not so much a fan of large number of thinp partitions, so as long as
> that is reasonably in control, we can possibly still use it. The big
> advantage though is, we nuke a thinp volume when the brick that uses that
> partition, moves out of that disk, and we get the space back, rather than
> having or to something akin to rm -rf on the backend to reclaim space.
Other way to achieve the same is to leverage the quota functionality of
counting how much size is used under a directory.
>
>
>
>>
>>
>> Today, gluster takes in a directory on host as a brick, and
assuming
>> we retain that, we would need to split this into multiple sub-dirs
>> and use each sub-dir as a brick internally.
>>
>> All these sub-dirs thus created are part of the same volume (due to
>> our current snapshot mapping requirements).
>>
>>
>>
>>
>> --
>> Pranith
>>
>
--
Pranith
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.gluster.org/pipermail/gluster-users/attachments/20170502/bc2b6c6e/attachment.html>