Redis and multicore servers

[Christian van der Leeden]

Hi,

can redis make effective use of multicore servers?
We're running it on a large EC2 instances with 4 cores and a lot of RAM.
I've read here that redis basically access the data in its core in a sequential
fashion. So is there a rule of thumb, e.g. one core per redis instance?
Or is redis running multiple worker threads depending on the # of cores?

In nginx you can tell the system how many cores you have and it will launch the
workers accordingly..

Christian

[Konstantin Merenkov]

Hi,

You run one instance of redis per core.

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[Jak Sprats]

> You run one instance of redis per core.

and use consistent hashing in your redis client

If you have 4 cores (and 1 NIC), using 2 cores for redis yields
optimal performance.

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[Demis Bellot]

If you have 4 cores (and 1 NIC), using 2 cores for redis yields optimal performance.

Is this right? I always thought on paper that 1 instance per core was the most efficient. I'm assuming the 2nd core is only useful when doing background saves? Its probably a good idea to ask if Redis uses a separate thread for IO?

- Demis

[Josiah Carlson]

It has to do with what processor is handling the network traffic. Jak
posted benchmarks on it in the last couple months, search the
archives.

- Josiah

[Christian van der Leeden]

Hi,

thanks for all the answers, I'll size accordingly :-)

Christian