GlusterFS rebalance weight based (WIP)

Please note I've to perform further testing to validate if it works as expected... but I would like to at least share it... 

On one of the GlusterFS instances I manage I have a wide variety of disk (brick) sizes.

5x 1TB
2x 2TB
1x 3TB

Although GlusterFS is currently not taking different disk sizes into count for 'rebalancing' the data.

After some searching on the Internet I noticed that there is a proposal to built it in into the GlusterFS Code (check this proposal on the Gluster Community).

So far the steps are actually pretty 'simple'...

Step 1)

Download the python scripts (as root)

# mkdir -p $HOME/glusterfs-weighted-rebalance
# cd $HOME/glusterfs-weighted-rebalance
# wget

Step 2)

Run the python script

# python -l glusterfs-cluster Backup_Volume
Here are the xattr values for your size-weighted layout:
Backup_Volume-client-0: 0x00000002000000000000000015557a94
Backup_Volume-client-1: 0x000000020000000015557a952aaaf523
Backup_Volume-client-2: 0x00000002000000002aaaf52440006fb2
Backup_Volume-client-3: 0x000000020000000040006fb35555ea41
Backup_Volume-client-4: 0x00000002000000005555ea426aab64d0
Backup_Volume-client-5: 0x00000002000000006aab64d19555c505
Backup_Volume-client-6: 0x00000002000000009555c506d5559fca
Backup_Volume-client-7: 0x0000000200000000d5559fcbffffffff
The following subvolumes are still mounted:
Backup_Volume-client-0 on /tmp/tmp2oBBLB/brick0
Backup_Volume-client-1 on /tmp/tmp2oBBLB/brick1
Backup_Volume-client-2 on /tmp/tmp2oBBLB/brick2
Backup_Volume-client-3 on /tmp/tmp2oBBLB/brick3
Backup_Volume-client-4 on /tmp/tmp2oBBLB/brick4
Backup_Volume-client-5 on /tmp/tmp2oBBLB/brick5
Backup_Volume-client-6 on /tmp/tmp2oBBLB/brick6
Backup_Volume-client-7 on /tmp/tmp2oBBLB/brick7
Don't forget to clean up when you're done.

Step 3)

Set the xattr trusted.glusterfs.size-weighted per brick to the values mentioned above:

# setfattr -n trusted.glusterfs.size-weighted -v 0x00000002000000000000000015557a94 /tmp/tmp2oBBLB/brick0
# setfattr -n trusted.glusterfs.size-weighted -v 0x000000020000000015557a952aaaf523 /tmp/tmp2oBBLB/brick1
# setfattr -n trusted.glusterfs.size-weighted -v 0x00000002000000002aaaf52440006fb2 /tmp/tmp2oBBLB/brick2
# setfattr -n trusted.glusterfs.size-weighted -v 0x000000020000000040006fb35555ea41 /tmp/tmp2oBBLB/brick3
# setfattr -n trusted.glusterfs.size-weighted -v 0x00000002000000005555ea426aab64d0 /tmp/tmp2oBBLB/brick4
# setfattr -n trusted.glusterfs.size-weighted -v 0x00000002000000006aab64d19555c505 /tmp/tmp2oBBLB/brick5
# setfattr -n trusted.glusterfs.size-weighted -v 0x00000002000000009555c506d5559fca /tmp/tmp2oBBLB/brick6
# setfattr -n trusted.glusterfs.size-weighted -v 0x0000000200000000d5559fcbffffffff /tmp/tmp2oBBLB/brick7

Step 4)

Unmount the temporary mounted volumes that were mounted by

# umount /tmp/tmp2oBBLB/*

Step 5) 

Start Gluster to rebalance the volumes:

gluster volume rebalance Backup_Volume start