[Gluster-users] distribute replicated volume and tons of questions

[Gandalf Corvotempesta]

2017-02-22 21:04 GMT+01:00 Joe Julian <joe at julianfamily.org>:
> dedup requires massive amounts of memory and is seldom worth it.

Yes, but compression is usefull

> Which is why I don't like building raid volumes that large.
>
> Personally, I only use raid on the servers to allow the disk i/o to match
> the network i/o. If that means those 12 8TB disks need to be 3 raid 0
> volumes (bricks) where I do sharded replica 3 or disperse volumes to meet my
> redundancy requirements, then that's what I'll do.

With gluster you could avoid raid, but you still need a filesystem on
each brick.
RAID or Non-RAID, an XFS fsck still need a week to fix (if able to
fix) a 12x 8TB chassis
in a non raid configuration. I don't think that fsck is run in
parallel, it will blow down the whole server.

> This is where people panic about using raid 0. If you've got the redundancy,
> that shouldn't be that scary. Do the math and actually calculate your
> reliability. I can still get 6 nines with raid 0 bricks. Not to say you
> should use raid 0, just to keep an open mind about what possibilities exist
> and engineer to your SLA requirements rather than over engineering for
> things that may not matter in the long run.

I don't like RAID (that's why i'm migrating to gluster)
I prefere to use gluster on single bricks