On 2016-10-18T11:36:42, Christian Balzer <ch...@gol.com> wrote:
> > Cache tiering in Ceph works for this use case. I assume you mean in
> > your UI?
> May well be, but Oliver suggested that cache-tiering is not supported with
> Hammer (0.94.x), which it most certainly is.
Right, we've got some success stories on Hammer already with it. Though
I much prefer Jewel too. ;-)
> > Though we all are waiting for Luminous to do away with the need for
> > cache tiering to do rbd to ec pools ...
> Well, there's the EC band-aid use case for cache-tiers, but they can be
> very helpful otherwise, depending on the size of working set/cache-pool,
> configuration of the cache-pool (write-back vs. read-forward) and
> specific use case.
Right. The main problem in my experience with cache tiering is that one
needs to know the answers to a bunch of questions most customers don't
have ;-) e.g., configuring the working set, flush/eviction policies,
etc. It's very helpful in some use cases, but mainly we're seeing it
used in the "band aid" mode. And I'd really love to get rid of those.
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"Experience is the name everyone gives to their mistakes." -- Oscar Wilde
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