Re: RAID6 stable enough for production?

[Rich Freeman <r-btrfs@thefreemanclan.net>]

On Wed, Oct 14, 2015 at 9:47 PM, Chris Murphy <lists@colorremedies.com> wrote:
>
> For that matter, now that GlusterFS has checksums and snapshots...

Interesting - I haven't kept up with that.  Does it actually do
end-to-end checksums?  That is, compute the checksum at the time of
storage, store the checksum in the metadata somehow, and ensure the
checksum matches when data is retrieved?

I forget whether it was glusterfs or ceph I was looking at, but some
of those distributed filesystems will only checksum data while in
transit, but not while it is at rest.  So, if a server claims it has a
copy of the file, then it is assumed to be a good copy and you never
realize that even though you have 5 copies of that file distributed
around the server you ended up using differs from the other 4.

I'm also not sure if it supports an n+1/2 model like raid5/6, or if it
is just a 2*n model like raid1.  If I want to store 5TB of data with
redundancy, I'd prefer to not need 10TB worth of drives to do it,
regardless of how many systems they're spread across.

--
Rich