[Gluster-users] Gluster pool help

[Michael Bushey]

I'm currently using GlusterFS 3.5.2 on a pair of production servers to
share uploaded files and it's been reliable and working well with just the
two servers. I've done some local tests of trying to add and remove servers
and the results have not been good. I'm starting to think I have the wrong
idea of what GlusterFS does and I'm trying to stick the square peg in the
round hole. Is there some config to say "number of replicas = number of
servers"?

My need is to have a copy of the data local on each server. If I have 5
servers, I want five copies of the data. Basically each server should have
it's own copy like it's a local ext4/zfs file-system, except it will
immediately sync files added or removed on the other servers. I'm not sure
the what the gluster definition of brick is, but I believe I want the
number of bricks to equal the number of servers (at least for this
particular file-system).

I've played around a bit and lost my data every time I've tried to add or
remove a node. There is plenty of documentation, but it all says the same
thing and doesn't answer the basics.

>From `gluster volume info`: Number of Bricks: 1 x 2 = 2

I'm assuming the middle 2 is the number of bricks. I have no clue why we're
multiplying by 1 to get itself.
http://gluster.org/community/documentation/index.php/Gluster_3.2:_Displaying_Volume_Information
- does not show this magic multiplication. The page for 3.3 does not exist.

We're cloud based and we want to be able to add and remove servers on the
fly. If for example I want to scale from 5 to 7 servers, it looks like I
need to create a new storage pool with 7 replicas. Would it be the most
logical to name my brick with the number of replicas? For example server1
to server5 already have /var/gluster/files5. I could then create
/var/gluster/files7 on server1 to server7, create the pool with 7 replicas,
then pick a machine like server1 to copy the data from /var/gluster/files5
to /var/gluster/files7, then destroy /var/gluster/files5. This seems
extremely convoluted but it does not appear possible to expand a storage
pool and expand the number of replicants with it.

Thanks in advance for help and your time to read this.
Michael
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