psp – Cody Hosterman

October 17, 2018July 31, 2019

Latency Round Robin PSP in ESXi 6.7 Update 1

This is my first (but certainly not last post) on the new path selection policy option in vSphere 6.7 Update 1. In reality, this option was introduced in the initial release of 6.7, but it was not officially supported until update 1.

So what is it? Well first off, see the official words from my colleague Jason Massae at VMware here:

https://storagehub.vmware.com/t/vsphere-storage/vsphere-6-7-core-storage-1/vsphere-6-7-u1-enhanced-round-robin-load-balancing/

Why was this PSP option introduced? Well the most common path selection policy is the NMP Round Robin. This is VMware’s built-in path selection policy for arrays that offer multiple paths. Round Robin was a great way to leverage the full performance of your array by actively using all of the paths simultaneously. Well…almost simultaneously.

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February 2, 2016February 2, 2016

Removing an incorrect SATP Rule

This was a fun one. I’ve posted in the past about changing and removing a SATP rule. That post, however, only works if the SATP rule is valid and you want to change or remove it for whatever reason. I am going to re-use the same image I made for that previous post, because it still holds true:

Anyway. The issue: Continue reading “Removing an incorrect SATP Rule”

May 14, 2014

Changing the default VMware Round Robin IO Operation Limit value for Pure Storage FlashArray devices

This is a topic I have posted about in the past but this time I am going to speak about it with the Pure Storage FlashArray. Anyone familiar with the VMware Native Multipathing Plugin probably knows about the Round Robin “IOPS” value which I will interchangeably also refer to as the IO Operation Limit. This value dictates how often NMP switches paths to the device–after a configured number of I/Os NMP will move to a different path. The default value of this is 1,000 but can be changed to as low as 1. For the highest performance Pure recommends changing this setting to 1 for all devices. The tricky thing is that it has to be done for every device on every host and doing this in a simple way isn’t immediately obvious. But here is the procedure.

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