Gluster users - Dec 2017 - How large the Arbiter node?

Hi,

I see gluster now recommends the use of an arbiter brick in "replica
2" situations.
How large should this brick be? I understand only metadata is to be stored.
Let's say total storage usage will be 5TB of mixed size files. How large
should such a brick be?

--
Sent from the Delta quadrant using Borg technology!

Nux!
www.nux.ro

Hi,

there is good suggestion here :
http://docs.gluster.org/en/latest/Administrator%20Guide/arbiter-volumes-and-quorum/#arbiter-bricks-sizing
<http://docs.gluster.org/en/latest/Administrator%20Guide/arbiter-volumes-and-quorum/#arbiter-bricks-sizing>
Since the arbiter brick does not store file data, its disk usage will be
considerably less than the other bricks of the replica. The sizing of the brick
will depend on how many files you plan to store in the volume. A good estimate
will be 4kb times the number of files in the replica.

BR,

Martin
> On 11 Dec 2017, at 17:43, Nux! <nux at li.nux.ro> wrote:
> 
> Hi,
> 
> I see gluster now recommends the use of an arbiter brick in "replica
2" situations.
> How large should this brick be? I understand only metadata is to be stored.
> Let's say total storage usage will be 5TB of mixed size files. How
large should such a brick be?
> 
> --
> Sent from the Delta quadrant using Borg technology!
> 
> Nux!
> www.nux.ro
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> http://lists.gluster.org/mailman/listinfo/gluster-users
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----- Original Message -----
> From: "Martin Toth" <snowmailer at gmail.com>
> To: "Nux!" <nux at li.nux.ro>
> Cc: "gluster-users" <gluster-users at gluster.org>,
"Gluster Devel" <gluster-devel at gluster.org>
> Sent: Monday, December 11, 2017 11:58:39 AM
> Subject: Re: [Gluster-users] How large the Arbiter node?
> 
> Hi,
> 
> there is good suggestion here :
>
http://docs.gluster.org/en/latest/Administrator%20Guide/arbiter-volumes-and-quorum/#arbiter-bricks-sizing
> Since the arbiter brick does not store file data, its disk usage will be
> considerably less than the other bricks of the replica. The sizing of the
> brick will depend on how many files you plan to store in the volume. A good
> estimate will be 4kb times the number of files in the replica.
You can see the explanation from the DEV here:

http://lists.gluster.org/pipermail/gluster-users/2016-March/025732.html

The 4k number was derived by adding 100 xattrs to a file:

[root at ravi4 brick]# touch file

[root at ravi4 brick]# ls -l file
-rw-r--r-- 1 root root 0 Mar  8 12:54 file

[root at ravi4 brick]# du file
*0       file**
*
[root at ravi4 brick]# for i in {1..100}
 > do
 > setfattr -n user.value$i -v value$i file
 > done

[root at ravi4 brick]# ll -l file
-rw-r--r-- 1 root root 0 Mar  8 12:54 file

[root at ravi4 brick]# du -h file
*4.0K    file**

The 4k number may be a little conservative but in all of the clusters I help
architect I follow that rule.

HTH!

-b

> 
> BR,
> 
> Martin
> 
> 
> 
> 
> On 11 Dec 2017, at 17:43, Nux! < nux at li.nux.ro > wrote:
> 
> Hi,
> 
> I see gluster now recommends the use of an arbiter brick in "replica
2"
> situations.
> How large should this brick be? I understand only metadata is to be stored.
> Let's say total storage usage will be 5TB of mixed size files. How
large
> should such a brick be?
> 
> --
> Sent from the Delta quadrant using Borg technology!
> 
> Nux!
> www.nux.ro
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> http://lists.gluster.org/mailman/listinfo/gluster-users
> 
> 
> _______________________________________________
> Gluster-users mailing list
> Gluster-users at gluster.org
> http://lists.gluster.org/mailman/listinfo/gluster-users