[Gluster-users] Need help to design a data storage

Gandalf Corvotempesta
Tue, 09 Aug 2016 17:38:12 -0000

Il 09 ago 2016 19:20, "Ashish Pandey" <aspandey at redhat.com>
ha scritto:
> 3 - EC with redundancy 2 that is 4+2
> The over all storage space you get is 4TB and any 2 bricks can be down at
any point of time. So it is as good as replica 3 but providing more space.

Not really.
With replica 3 i can set the brick location on different servers so that i
can loose multiple servers and not only multiple bricks

What about EC? Are redundant data spread across multiple servers? If not,
multiple replica would be placed on the same server. I can loose 2 bricks
(2 disks) but what if I'll loose the whole server with both bricks on it?
And when a server fails, multiple bricks are affected .........

replica 3 is like a raid10 with 3 disks in each mirror (3 failed bricks in
the same replica set=data loss). EC is like raid6 (3 failed bricks in the
whole cluster=data loss). The first is safer than the latter but has a huge
waste of space.
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