Hi Gluster Gurus,
Due to some hasty decisions and inadequate planning/testing, I find
myself with a single-brick Distributed gluster volume. I had initially
intended to extend it to a replicated setup with an arbiter based on a
post I found that said that was possible, but I clearly messed up in the
creation of the gluster as I have since come to understand that a
distributed brick cannot be converted to replicated.
The system is using gluster 5.4 from Debian Repos.
So it seems I will have to delete the existing volume and create a new
one, and I am now thinking it would be more future-proof to go with a
2x2 distributed-replica anyway. Regardless, I am trying to find a path
from old gluster volume to new gluster volume with a minimum of
downtime. In the worst case scenario, I can wipe the existing gluster,
make a new one and restore from backup. But I am hoping I can re-use
the existing brick in a new gluster configuration and avoid that much
downtime.
So I synced the whole setup into a test environment, and thanks to a
helpful post on this list I found this article:
https://joejulian.name/post/glusterfs-path-or-a-prefix-of-it-is-already-part-of-a-volume/
so I tried wiping the gluster and recreating, and removed the attributes
and the .gluster directory from the brick, and it initially seems to
work in my test environment, kinda. When I do the gluster create
command and include the existing brick as the first one and leave it for
a couple days, the replicated brick ends up with only about 80% of the
data. tested a few times and that is pretty consistent.
if I try with straight 2 replicated bricks, that never really changes
after triggering multiple heals, and when I list files in gluster mount
the file attributes such as owner/group/perms/data are replaced with
question marks on a significant amount of files and those files are not
ls'able except as part of a directory.
If I try with the 2x2 setup, the replicated brick also has only about
80% of the data initially, and after a few days of rebalancing df shows
the two new distributed bricks to be almost exactly the same size, but
the replica of the original/reused brick still end up being 5-7% less
than the original, and the same symptoms of files not being accessible
and having question marks for permissions/owner/data/etc persist.
And this takes days, so definitely not faster than restoring from backup.
I have been looking for other solutions, but if they exist so far I have
not found them. Wondering if someone could provide some guidance or
point me at a solution, or inform me if restoring from backup is really
the best way forward?
--
Bob Miller
Cell: 867-334-7117
Office: 867-633-3760
Office: 867-322-0362
www.computerisms.ca
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