[Gluster-users] Exorbitant cost to achieve redundancy??
jaw171 at pitt.edu
Wed Feb 15 06:30:58 PST 2012
On 02/14/2012 01:25 PM, John Mark Walker wrote:
> ----- Original Message -----
>> I'm currently fighting to get GlusterFS replica in an HPC environment
>> but the "wasting half the space" argument is hard to fight when
>> a tight budget. There really is no waste at all, the space is being
>> used for full server redundancy (IMHO you need server redundancy, not
>> just disk redundancy) and in some use-cases, increased performance
>> other use-cases replica is slower).
> I think this gets to the heart of the matter. This is very much on our minds as we look at future roadmaps.
> For now, replica 2 + RAID underneath is a valid solution for the vast majority of use cases.
True, but it seems like at some point the cost of N+N just looks silly
(think if you need 2,000 servers to get the usable space of 1,000 of them).
> There shouldn't be many cases where replica 3 is absolutely necessary - not when you utilize a decent RAID card.
> To pose the issue in a slightly different light, what would you want future behavior to be? Is erasure coding something that you view as essential in the near future?
By "erasure coding" I assume you mean "some RAID 5/6-like data recovery
with parity". I think this should be something to investigate and see
if it is plausible to build. At the very least it opens GlusterFS to
more use-cases and more design choices.
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