On 09/14/2014 05:11 PM, Andrei Mikhailovsky wrote: > Hello guys, > > Was wondering if anyone uses or done some testing with using bcache or > enhanceio caching in front of ceph osds? > > I've got a small cluster of 2 osd servers, 16 osds in total and 4 ssds > for journals. I've recently purchased four additional ssds to be used > for ceph cache pool, but i've found performance of guest vms to be > slower with the cache pool for many benchmarks. The write performance > has slightly improved, but the read performance has suffered a lot (as > much as 60% in some tests). > > Therefore, I am planning to scrap the cache pool (at least until it > matures) and use either bcache or enhanceio instead. We're actually looking at dm-cache a bit right now. (and talking some of the developers about the challenges they are facing to help improve our own cache tiering) No meaningful benchmarks of dm-cache yet though. Bcache, enhanceio, and flashcache all look interesting too. Regarding the cache pool: we've got a couple of ideas that should help improve performance, especially for reads. There are definitely advantages to keeping cache local to the node though. I think some form of local node caching could be pretty useful going forward. > > Thanks > > Andrei > > > _______________________________________________ > ceph-users mailing list > ceph-users at lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >
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