[Gluster-users] Add single brick to dispersed volume?

[William Ferrell]

Hello,

I'm just getting started with GlusterFS, so please forgive what's
probably a newbie question. I searched the mailing list archives and
didn't see anything about this, so I figured I'd just ask.

I'm running four VMs on a single machine to learn the ropes a little
bit. Each VM is set up the same way, with an OS disk and a separate
disk (formatted as xfs) for use as a brick.

Initially I created a dispersed volume using three bricks with
replication 1. That seems to work pretty well. Now I'm trying to add a
fourth brick to the volume, but am receiving an error when I try:

root at gluster1:~# gluster volume add-brick test1 gluster4:/export/gfs/brick
volume add-brick: failed: Incorrect number of bricks supplied 1 with count 3

Have I misunderstood how dispersed volumes work? I was under the
impression (from the documentation at
https://docs.gluster.org/en/latest/Administrator%20Guide/Managing%20Volumes/#expanding-volumes)
that bricks could be added to dispersed volumes so long as they were
added N at a time, where N is the replication value. This error
message makes it sound like I need to add three bricks at once
instead.

Is it possible to expand dispersed volumes like this? Or would I be
better off doing this with a "regular" replicated volume? I'm
interested in using dispersed volumes because of the space savings,
but I'm a bit confused about how expansion works for them.

Thanks for you help!