- VMware vCenter 5.5 Update 2
- ESXi 5.5 Update 2
- Hitachi HUS 110
- After the upgrade from ESXi 5.0 to 5.5 Update 2 ESXi host got disconnected from vCenter
- We were able to ping host however unable to access/add from vCenter
- All the VMs on the host are also unresponsive.
After analyzing the logs here is what we observed the problem was with ATS reservations failing (ATSF) for the LUNs
Step 1 – We verified ATSF values on ESXi Hosts using following procedure
enter command \”esxtop\” ,then:press u, next f, next o & p to select VAAISTATS and VAAILATSTATS/cmd fields.
check the value in column ATSF, ideally it should be \”0\”
if you see high number of ATSF it means you are having issue with failed ATS commands.
Step 2 – We verified and ensured that VAAI features are enabled on the ESXi host from a console or SSH session using this command in the below mentioned KB Article
esxcli system settings advanced list -o /VMFS3/HardwareAcceleratedLocking
Step 3 – We checked storage and after analyzing logs with Hitachi we figured out that VAAI is not enabled by default in HUS 110
Also as per Hitachi it is a common error post upgrading to 5.5 and the VAAI is not enabled in HUS 110
In order to enable VAAI feature on HUS 110 we need to enable following Host Mode options on the ESXi Host Groups using SNM2
- Enable Unique Extended COPY Mode
- Enable Unique Write Same Mode
- Enable DP Depletion Detail Reply Mode
We enabled options and rebooted the hosts to release ATSF
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