Verifing that ATS is Configured on a Datastore in a VMware Support Bundle
Identifying datastore ATS Configuration on VMware ESXi
Step 1:
Since we only care about datastores (not Raw Device Maps (RDMs)) on Pure Storage we will find our applicable LUNs in the "esxcfg-scsidevs -m.txt" file under the "commands" folder in a VMware Support Bundle. Below is an example of what a line from there will look like:
There are several things that we want to identify from this output; the first is the "NAA Identifier". This is important because anything starting with "naa.624a937" is a Pure Storage LUN. Once we have a Pure Storage LUN we then want to take note of the "VMFS UUID" number (i.e. 53c80075-7ddcc5ba-7d03-0025b5000080). The reason why we focus on this instead of the "User-Friendly Name" is because the customers can choose any name they want in that option. If we choose the VMFS UUID then we are guaranteed to know we are referring to a Pure Storage LUN since that is a uniquely generated ID that the vCenter Server assigns to individual LUNs.
Step 2:
Once we have this information the next step is to search for the "vmkfstools" text file that contains the File System information on this device; this will also be found in the "commands" folder you already reside in. An example of what the text file will look like is as follows:
vmkfstools_-P--v-10-vmfsvolumes53c80075-7ddcc5ba-7d03-0025b5000080.txt
Notice above our "VMFS UUID" is contained in the file name (in red). We can now search this file for the "Mode" it is running in. An example of what this line will look like, if configured properly, is as follows:
Mode: public ATS-only
If the datastore is not configured properly it will look as follows:
Mode: public
If the datastore is showing a "public" mode then we know that this datastore is misconfigured and we'll be receiving an excessive amount of SCSI-2 Reservations from the ESXi Hosts. This means that locking tasks are not being offloaded to the FlashArray.
Obviously if the customer has a lot of LUNs this process above can take a while, so it is best to script this. I have listed below a simple one liner that will do this for you if you would like to use this instead of going through each LUN one-by-one:
grep "naa.624a937" esxcfg-scsidevs_-m.txt | awk '{print $3}' > Pure-LUNs.txt;while read f;do cat vmkfs*$f.txt |grep -e "Mode:" -e "naa.624a937";echo;done < Pure-LUNs.txt
NOTE: This command is able to be copied & pasted then used on any ESXi Host that is 5.0 and higher, as long as you are in the "commands" folder of the ESXi Host you want to verify.
Resolution
Once we have the misconfigured LUNs identified the customer can use the VMware KB listed below to resolve the issue:
Link to VMware KB: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1033665
Follow the steps outlined in the "Changing an ATS-only volume to public". Simply change the "0" they are setting to a "1" in the listed command they provide to turn ATS-only back on. It is important that the customer read all of the steps before continuing forward and reading the notes & caveats.
Alternatively, and also much less of a headache, the customer can simply create a new LUN from the FlashArray and mount it to the applicable ESXi Host(s). Once the new VMFS datastore is created they can verify that ATS is properly configured. Once confirmed the new datastore has ATS enabled can then migrate the Virtual Machines from the misconfigured datastore to the newly configured datastore. After everything has been moved from the old datastore and they have confirmed all is working well, they can simply destroy the old LUN. This is much easier to do and is typically what should be recommended as the first step.
If there are any questions please reach out to a fellow colleague or Support Escalations team member for assistance.
Confirming the SCSI-2 Reservations are Happening
If VMware is not configured as per best practice expectations (ATS Enabled) then we may see SCSI-2 Reservations in our logs. This is how you can check to see if that's happening: