[Gluster-users] Replica 3 scale out and ZFS bricks

[Alexander Iliev]

Hi list,

I am in the process of planning a 3-node replica 3 setup and I have a 
question about scaling it out.

 From what I understood, in order to be able to scale it one node at a 
time, I need to set up the initial nodes with a number of bricks that is 
a multiple of 3 (e.g., 3, 6, 9, etc. bricks). The initial cluster will 
be able to export a volume as large as the storage of a single node and 
adding one more node will grow the volume by 1/3 (assuming homogeneous 
nodes.)

Please let me know if my understanding is correct.

My plan is to use ZFS as the underlying system for the bricks. Now I'm 
wondering - if I join the disks on each node in a, say, RAIDZ2 pool and 
then create a dataset within the pool for each brick, the GlusterFS 
volume would report the volume size 3x$brick_size, because each brick 
shares the same pool and the size/free space is reported according to 
the ZFS pool size/free space.

How should I go about this? Should I create a ZFS pool per brick (this 
seems to have a negative impact on performance)? Should I set a quota 
for each dataset?

Does my plan even make sense?

Thank you!

Best regards,
-- 
alexander iliev