If the rbd cache = false, and run the same two tests, the read iops is
stable(this is a new cluster without stress):
109 274471 2319.41 9500308.72
110 276846 2380.81 9751782.65
111 278969 2431.40 9959023.39
112 280924 2287.21 9368428.23
113 282886 2227.82
Do you have test results for the same test without caching?
I have seen periodic stalls in any RBD IOP/s benchmark on ceph. The benchmarks
create IO requests much faster than OSDs can handle them. At some point all
queues run full and you start seeing slow ops on OSDs.
I would also prefer if IO
Hmm, so maybe your hardware is good enough that cache is actually not helping?
This is not unheard of. I don't really see any improvement from caching to
begin with. On the other hand, a synthetic benchmark is not really a test that
utilises the good sides of cache (in particular, write merges w
