Hi all - is there a safe way to shrink an active gluster volume without
losing files?
I've used remove-brick before, but this causes the files on that brick
to be removed from the volume. Which is fine for some situations.
But I'm trying to remove a brick without losing files. This is because
our file usage can grow dramatically over short periods. During those
times we add a lot of buffer to our gluster volume, to keep it at about
50% usage. After things settle down and file usage isn't changing as
much, we'd like to remove some bricks in order to keep usage at about
80%. (These bricks are AWS EBS volumes - we want to remove the bricks to
save a little $ when things are slow.)
So what I'd like to do is the following. This is a simple distributed
volume, no replication.
* Let gluster know I want to remove a brick
* No new files will go to that brick
* Gluster starts copying files from that brick to other bricks,
essentially rebalancing the data
* Once all files have been duplicated onto other bricks, the brick is
marked as "removed" and I can do a normal remove-brick
* Over the course of this procedure the files are always available
because there's always at least one active copy of every file
This procedure seems very similar to replace-brick, except the goal
would be to evenly distribute to all other active bricks (without
interfering with pre-exiting files), not one new brick.
Is there any way to do this?
I *could* just do my remove-brick, then manually distribute the files
from that old brick back onto the volume, but that would cause those
files to become unavailable for some amount of time.
Many thanks for all your help,
- brian
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