[Gluster-users] cluster.min-free-disk separate for each, brick

Deyan Chepishev - SuperHosting.BG dchepishev at superhosting.bg
Wed Aug 17 23:50:11 UTC 2011

Whit Blauvelt wrote:
> Hi Deyan,
> This may not be a useful suggestion, but why not just partition your storage
> so that your bricks remain uniform?

==> Well this is a good suggestion unless you already have non uniform storage 
with huge difference in brick sizes. The thing is that I was using one single fs 
(XFS) which is over LVM and I was growing it each time I add new hdds. However I 
realized that this could bring me a lot of troubles and decided to switch to 
glusterfs, which brings the smaller bricks in the game. So basically I dont have 
enough space to transfer the huge brick to a smaller bricks and that is why I 
got to this situation.

> When you get more disk capacity because
> you've got 3TB drives instead of 2TB in RAID5, so that you have 15TB rather
> than 10TB per system, why not split the storage into 10TB and 5TB
> partitions, use the 10TB for a uniform-sized brick to add to an existing
> Gluster storage area, and then take your 5TB partitions and set up another
> Gluster share using that as your uniform brick size for it?

===> I am trying to build something like cloud storage using Gluster which 
basically does not suit to your suggestion. If I wanted to have partitioned 
storage I would not have chosen glusterfs. What I was imaging was, just add new 
bricks no matter what size it will handle them automatically, which it does not. 
If I knew this before I probably would not choose gluster.

Thank you

> Might not fit your requirements at all - depends on what you're storing and
> whether it makes sense to separate it into a couple of different areas.
> Best,
> Whit
> On Wed, Aug 17, 2011 at 04:28:42PM +0300, Deyan Chepishev - SuperHosting.BG wrote:
>> Hello,
>> This is really bad news, because I already migrated my data and I
>> just realized that I am screwed because Gluster just does not care
>> about the brick sizes.
>> It is impossible to move to uniform brick sizes.
>> Currently we use 2TB  HDDs, but the disks are growing and soon we
>> will probably use 3TB hdds or whatever other larges sizes appear on
>> the market. So if we choose to use raid5 and some level of
>> redundancy (for example 6hdds in raid5, no matter what their size
>> is) this sooner or later will lead us to non uniform bricks which is
>> a problem and it is not correct to expect that we always can or want
>> to provide uniform size bricks.
>> With this way of thinking if we currently have 10T from 6x2T in
>> hdd5, at some point when there is a 10T on a single disk we will
>> have to use no raid just because gluster can not handle non uniform
>> bricks.
>> Regards,
>> Deyan

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