Performance impact of using ssd partitions vs. dedicated drive


#1

Hello there, we will deploy our project on servers with dual Intel 3.5k DC 480gb SSDs. Unfortunately, we have only 2 SSDs in the machine, without any hardware raid. Because we obviously need to boot from something (USB Flash drive is an option, though not our favorite one).

If we partition one of the drives to store the OS and all logfiles etc, is there theoretically a big performance impact on the AS storage on the same device? Or is it ‘just’ that AS can not utilize some of the IOPS now spent on the OS partition?

So the question is: can we expect more like 80% of performance of a dedicated usage or is it more like 30-50%? What is the difference within the AS stack when using a partition vs. full device? My understanding is, that theoretically nothing from the OS should interfere with AS (as there is no file system involved on AS partition?)

It would be cool if anybody could clarify this, as we come from a mindset of “don’t you ever dare to run it on anything less than the whole device” and don’t know whether partitions might be enough for our use case.

Cheers from Germany, Manuel


#2

I’m not aware of a performance penalty other than some IOPs being used by the system. The major penalty comes when you mount the device and have Aerospike use the device through a filesystem.

That said, Aerospike does expect all of the devices be the same size, so if you take 60GB out of one for the OS, it is equivalent to taking 60 GB from them all. To work around this you could you could divide the drives into equal size partitions (e.g. 5x96GBx2) and give the OS one of the partitions and the rest to Aerospike.


#3

Thanks for providing this valueable insight into operations with partitioned ssds! This increases our deployment options (hardware not owned by us) by far.