Does Aerospike Installation changes Kernel/System variables which affect other apps?


#1

Hi, After I installed Aerospike (3.15.0.1), the dequeue rate of redis client on the same machine slows down. The redis server is on different machine.
This didnt observed before the Aerospike installation. Also One more consumer dequeuing from the same redis server on different machine didnt face any issues.

There can be multiple threads upto 40 using Redis & Aerospike and belongs to same application running on Tomcat. We have tried restarting Tomcat after stopping Aerospike after which we face the same issue.

This was occuring even if the Aerospike server is stopped. Please help to find whats happening. Are there any system/kernel variables modified during Aerospike installation which affects Redis performance?

My Aerospike config is single-bin in-memory configuration and there was no instance of Aerospike installed earlier on this machine.

Please help to find the issue. Thanks in Advance


#2

Aerospike will change two kernel params, kernel.shmmax and kernel.shmall . https://www.aerospike.com/docs/operations/troubleshoot/startup/index.html#warning-messages-on-starting-aerospike

Do not run two databases on the same machine, especially not Aerospike and something like Redis.

As opposed to Redis, which cannot vertically scale and requires you to run multiple instances to use your machine’s CPU cores, Aerospike is a multicore, multithreaded database, and will try to use all the resources available.


#3

Thanks Ronen. But we are using Redis as Queue on different machine. Only the redis client in the machine which aerospike exists. Using only LPUSH & RPOP commands. I will be very much happy if Aerospike supports this datastructure. Else it would be appreciated if you can suggest low latency scalable Message Queue.

Also please suggest if I can install & run Aerospike as non root user.

Thanks in Advance


#4

You could use taskset to make sure Aerospike doesn’t run on some of your cores. For example the following would leave the first 8 cores free:

taskset -p ffffff00 <PID of asd>

See Running as Non Root


#5

Thank for the suggestion Ronen. Will there be any impact on aerospike performance if I increase the shmmax and shmall than the value set by aerospike during installation?

In my case, the aerospike has lowered these values during installation. I need to reset these to my original.


#6

It should not affect you as an Aerospike CE user.


#7

Thanks Ronen. Just for understanding may I know in what way it will affect Enterprise Edition users. I mean, in EE, will there be a performance impact on increasing this value? Or the philosophy itself entirely different. Can you please throw some light?