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effective_io_concurrency with an SSD SAN?

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effective_io_concurrency with an SSD SAN?

Evan D. Hoffman
Given a system with 32 cores, an SSD SAN with 48x drives, and 2x 8Gbps
paths from the server to the SAN, what would be a good starting point
to set effective_io_concurrency?  I currently have it set to 32, but I
kind of feel like the right setting would be "2" since we have two
paths.  We don't often saturate both links but it does happen from
time to time.


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Re: effective_io_concurrency with an SSD SAN?

Samrat Revagade
>Given a system with 32 cores, an SSD SAN with 48x drives, and 2x 8Gbps
>paths from the server to the SAN, what would be a good starting point
>to set effective_io_concurrency?  I currently have it set to 32, but I
>kind of feel like the right setting would be "2" since we have two
>paths.  We don't often saturate both links but it does happen from
>time to time.

One assumption about optimal value is that, it is usually the number of data drives participating in the I/O system excluding the parity drives.
here is the article about setting it in Postgres Plus Advanced Server.
Have a look at it if you find it useful for normal PostgreSQL setup:
http://www.enterprisedb.com/docs/en/8.3R2/perf/Postgres_Plus_Advanced_Server_Performance_Guide-17.htm
Greetings,
Samrat Revagade,
NTT DATA OSS Center Pune, India.
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