After reading my blog I thought I would expand a bit on the ON/OFF capabilities and what they actually turn on and off when it comes to VAAI. I kind of threw a lot out there and wanted to make a little more sense out of the mess I made. All the stuff I wrote about installing and validating, that's great, but let's talk more about WHAT those on/off switches actually turn on and off.
In most cases this stuff is all on by default and in most cases you won't need to turn it off. But what if your boss comes to you and says, "Hey prove to me this VAAI stuff works!" or say you want to try and find a bottleneck, you can turn individual settings on and off to test. Please do be careful!
The neat thing about ATS_Only is with VMFS5 datastores, the default is ATS! Do be careful with this one, please don't play in your production environment! :-)
# vmkfstools -Ph -v1 /vmfs/volumes/vaai_iscsi2
# vmkfstools --configATSOnly 0 /dev/disks/<disk name>
# vmkfstools --configATSOnly 1 /dev/disks/<disk name>
Yesterday I showed the GUI way to set ATS, XCOPY and Write_Same if you'd rather use the GUI.
Until Next Time!