greg@xxxxxxxxxxx said:
> >
> The rados benchmark was run on one of the OSD
> machines. Read and write results looked like this (the
> objects size was just the default, which seems to be 4kB):
> Actually, that's 4MB. ;)
Oops! My plea is that I was the victim of a
man page bug:
bench seconds mode [ -b objsize ] [ -t threads ]
Benchmark for seconds. The mode can be write or read. The
default object size is 4 KB, and the default number of simulated
threads (parallel writes) is 16.
> Can you run # rados bench -p pbench 900 write -t 256
> -b 4096 and see what that gets? It'll run 256 simultaneous 4KB writes. (You
> can also vary the number of simultaneous writes and see if that impacts it.)
Here's the new benchmark output:
Total time run: 900.880070
Total writes made: 537187
Write size: 4096
Bandwidth (MB/sec): 2.329
Stddev Bandwidth: 2.57691
Max bandwidth (MB/sec): 12.6055
Min bandwidth (MB/sec): 0
Average Latency: 0.429315
Stddev Latency: 0.891734
Max latency: 19.7647
Min latency: 0.016743
> However, my suspicion is that you're limited by metadata throughput here. How
> large are your files? There might be some MDS or client tunables we can
> adjust, but rsync's workload is a known weak spot for CephFS. -Greg
The file size is generally small. Here's the distribution:
http://ayesha.phys.virginia.edu/~bryan/filesize.png
The mean is about 2.5 MB.
Bryan
--
========================================================================
Bryan Wright |"If you take cranberries and stew them like
Physics Department | applesauce, they taste much more like prunes
University of Virginia | than rhubarb does." -- Groucho
Charlottesville, VA 22901|
(434) 924-7218 | bryan@xxxxxxxxxxxx
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