On 6/16/11 3:22 PM, Mark Schoy wrote:
Hi,
I set up a Solr instance with 512 cores. Each core has 100k documents and 15
fields. Solr is running on a CPU with 4 cores (2.7Ghz) and 16GB RAM.
Now I've done some benchmarks with JMeter. On each thread iteration JMeter
queriing another Core by random. Here are the results (Duration: each with
180 second):
Randomly queried cores | queries per second
1| 2016
2 | 2001
4 | 1978
8 | 1958
16 | 2047
32 | 1959
64 | 1879
128 | 1446
256 | 1009
512 | 428
Why are the queries per second until 64 constant and then the performance is
degreasing rapidly?
Solr only uses 10GB of the 16GB memory so I think it is not a memory issue.
This may be an OS-level disk buffer issue. With a limited disk buffer
space the more random IO occurs from different files, the higher is the
churn rate, and if the buffers are full then the churn rate may increase
dramatically (and the performance will drop then). Modern OS-es try to
keep as much data in memory as possible, so the memory usage itself is
not that informative - but check what are the pagein/pageout rates when
you start hitting the 32 vs 64 cores.
--
Best regards,
Andrzej Bialecki <><
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