[Gluster-users] How to convert a Distribute volume to Distribute-Replicate when adding a new brick

[Burnash, James]

Well, I've searched through the mailing list and have been unable to find an answer to the problem I'm currently facing.

I am currently in the middle of migrating from my old 6 server storage pool running GlusterFS 3.0.4 to a new pool that will eventually consist of the same machines all running GlusterFS 3.1.1.

My initial setup was all 6 servers setup as Distribute-Replicate, so that I had 3 pairs of mirrors.

To effect the conversion and minimize downtime, I took down 1 of each of the mirrors and converted them (with different storage hardware) to run GlusterFS 3.1.1. This all worked fine, and production is currently running on the following setup:

(1) Server running a read-write storage pool in Distribute mode configured like this:
# gluster volume info

Volume Name: pfs-rw1
Type: Distribute
Status: Started
Number of Bricks: 2
Transport-type: tcp
Bricks:
Brick1: jc1letgfs16-pfs1:/export/read-write/g01
Brick2: jc1letgfs16-pfs1:/export/read-write/g02
Options Reconfigured:
performance.stat-prefetch: on
performance.cache-size: 2GB

Then I have:

(2) Servers running the read-only pools in this configuration:
gluster volume info

Volume Name: pfs-ro1
Type: Distributed-Replicate
Status: Started
Number of Bricks: 10 x 2 = 20
Transport-type: tcp
Bricks:
Brick1: jc1letgfs17-pfs1:/export/read-only/g01
Brick2: jc1letgfs18-pfs1:/export/read-only/g01
Brick3: jc1letgfs17-pfs1:/export/read-only/g02
Brick4: jc1letgfs18-pfs1:/export/read-only/g02
Brick5: jc1letgfs17-pfs1:/export/read-only/g03
Brick6: jc1letgfs18-pfs1:/export/read-only/g03
Brick7: jc1letgfs17-pfs1:/export/read-only/g04
Brick8: jc1letgfs18-pfs1:/export/read-only/g04
Brick9: jc1letgfs17-pfs1:/export/read-only/g05
Brick10: jc1letgfs18-pfs1:/export/read-only/g05
Brick11: jc1letgfs17-pfs1:/export/read-only/g06
Brick12: jc1letgfs18-pfs1:/export/read-only/g06
Brick13: jc1letgfs17-pfs1:/export/read-only/g07
Brick14: jc1letgfs18-pfs1:/export/read-only/g07
Brick15: jc1letgfs17-pfs1:/export/read-only/g08
Brick16: jc1letgfs18-pfs1:/export/read-only/g08
Brick17: jc1letgfs17-pfs1:/export/read-only/g09
Brick18: jc1letgfs18-pfs1:/export/read-only/g09
Brick19: jc1letgfs17-pfs1:/export/read-only/g10
Brick20: jc1letgfs18-pfs1:/export/read-only/g10
Options Reconfigured:
performance.cache-size: 2GB
performance.stat-prefetch: on

Now that all of production is off the old setup, I want to take one of those servers (suitably reconfigured with 3.1.1) and make it participate in the read-write pool, but change the Type to Distributed-Replicate.

Is this possible?

Thanks

James Burnash, Unix Engineering


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