On 7/31/12 7:31 AM, Mehdi Abaakouk wrote:
Hi all,
I have updated the how-to here:
http://ceph.com/wiki/Benchmark
And published the results of my latest tests:
http://ceph.com/wiki/Benchmark#First_Example
I haven't actually used bonnie++ myself, but I've read some rather bad
reports from various other people in the industry. Not sure how much
it's changed since then...
https://blogs.oracle.com/roch/entry/decoding_bonnie
http://www.quora.com/What-are-some-file-system-benchmarks
http://scalability.org/?p=1685
http://scalability.org/?p=1688
I'd say to just take extra care to make sure that that it's behaving the
way you intended it to (probably good advice no matter which benchmark
you use!)
All results are good, my benchmark is clearly limited by my network
connection ~ 110MB/s.
Gigabit Ethernet is definitely going to be a limitation with large block
sequential IO for most modern disks. I'm concerned with your 6 client
numbers though. I assume those numbers are per client? Even so, with
10 OSDs that performance is pretty bad! Are you getting a good
distribution of writes across all OSDs? Consistent throughput over time
on each?
In exception of the rest-api bench, the value seems really low.
We've especially noticed that radosgw performance is lower with small IO
sizes. There's a lot of potential places where this could be happening
between the client, radosgw, and Apache. It's something we're going to
be looking at over the next couple of months.
I have configured radosgw with this:
http://ceph.com/docs/master/radosgw/config/
I clean disk cache on all servers before the bench,
and start rest-bench for 900 seconds with default value.
Is my rest-bench result normal ? Have I missed something ?
You may want to try increasing the number of concurrent rest-bench
operations. Also I'd explicitly specify the number of PGs for the pool
you create to make sure that you are getting a good distribution.
Don't hesitate if you need more informations on my setup.
And then, I have another question about how is the Standard Deviation
calculated with rados bench and rest-bench ? with the reported value
printed each second by the benchmark client ?
If yes, when latency is too high, the reported bandwith is sometime zero,
then has the calculated StdDev for bandwith a sens ?
Good question! I'll ping the author of that code to respond.
Cheers,
Thanks,
Mark
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