Do I still need to tune storage in Linux?

Here at Violin we have a number of best practice recommendations for all types of OS and databases. Some customers follow all of them, whilst others require persuading.

One recommendation that can sometimes cause debate is utilizing the UDEV rules to optimize the IO schedulers in Linux. Sometimes this can make a dramatic difference, other times very little.

A colleague of mine has recently been investigating slightly unpredictable performance on a VM running RHEL compared to SLES. It turns out that the UDEV recommendations had not been applied to either. It seems that the defaults in SLES 11 are better optimized by default for high performance in Virtual Machines.

 

RHEL_Orion_single_vCPU

SLES_Orion_Single_vCPU

 

Both VMs in the above example are deliberately limited to a single vCPU and hit limits of guest CPU before stretching the storage.
But in this situation we saw up to a 15% improvement on SLES and 30% improvement on RHEL.
So different flavours have different benefits, but even at these modest rates of performance there is a significant benefit in both bandwidth and latency.

To get the recommended best practices for your environment just ask your Violin contact.

 

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