[Gluster-users] rebalance on large filesystems

[ML]

Hi there,

I'm looking for the community's opinion on a gluster volume rebalance 
I'm hestitating to start :)

Here is my config :

Volume Name: nas-3
Type: Distributed-Replicate
Status: Started
Number of Bricks: 2 x 2 = 4
Transport-type: tcp
Bricks:
Brick1: 192.168.0.1:/home/nas-3
Brick2: 192.168.0.2:/home/nas-3
Brick3: 192.168.0.3:/home/nas-3
Brick4: 192.168.0.4:/home/nas-3
Options Reconfigured:
performance.quick-read: off
performance.cache-size: 500MB
performance.io-thread-count: 32
transport.address-family: inet
performance.readdir-ahead: on

The bricks are constitued of 4 gluster servers version 3.10.12 :

192.168.0.1 + 192.168.0.2 = 2 x 22 TiB (global usage : 86%)
192.168.0.3 + 192.168.0.4 = 2 x 7   TiB (global usage : 40%) (this 2 
bricks came 1 year after the 2 first ones, without rebalance after went 
live)

Actual usage :

on 192.168.0.1 + 192.168.0.2 : /home/nas-3 = 2 x 14,5TiB (Items: 49327658)
on 192.168.0.3 + 192.168.0.4 : /home/nas-3 = 2 x 2,8TiB (Items: 10343981)

I need advice regarding :

- Should I rebalance to fill the 2 x 7.2TiB servers ? (I need space on 
the 22TiB servers)
- Is rebalance process dividing files based on disk usage for each 
connected brick ? (I'm afraid to see my 7.2 TiB servers become full)
- Given the number of files stored, how to get an idea of the time 
needed for the rebalance process to be complete ?


Thank you for reading me & considering answering :))

(If there's a gluster consultant you would recommand for these 
questions, please let me know)

Quentin