power cycle storage

[ndmuser]

I have four esxi 5.0 hosts connected to EMC VNX5300 box via FC and to IBM DS3512 box via iSCSI. There are several datastores located on each storage device containing several VMs. I use EMC VNX box as faster storage for Heartbeat. We need to power cycle EMC VNX5300 to fix some mostly cosmetic issue with it. I am wondering what would be the proper steps on VMware side to prepare to power cycle this box?  I am planning to migrate a couple of mission critical VMs to slower IBM storage, also change Heartbeat datastores from EMC to IBM datastores. I also got OK to shut down all remaining VMs on EMC...Please share your thought

Thanks a lot!

[jedijeff]

If the storage is going to be down for an extended period of time, I may be worried about an APD(all paths down) condition which could cause your hosts to disconnect from vcenter eventually. If this is a quick storage reboot, I am doubting that the APD would affect you.

That said, you could mask all the Luns before you power off the storage, and then unmask them afterwards to ensure the Esx hosts will definitely not have any issues.

Here is a KB on it, and it can be kind of tricky to be honest:

VMware KB: Masking a LUN from ESX and ESXi using the MASK_PATH plug-in

[ndmuser]

Thank you for your reply! What is considered extended period of time? According to EMC CE the whole process of power cycle will take around one hour. I guess it includes everything.

Do you think  one hour is pretty short interval to mask LUNs?

Thanks

[jedijeff · Accepted solution]

I *personally* would not mask for an hour. However, there have been many improvements since ESXi 5.0 for the APD. I ran into this on ESXi 5.1 for about half a day and never had any issues, when someone deleted Luns off an array and never bothered telling us and ESX kept looking for them. I would try to get some information on how APD worked in ESX 5.0, but I would think an hour would be ok. Just don't shoot me if you have any issues. And the vmware knowlegebase has tons of articles on APD.

[ndmuser]

No shooting I promise Cross my fingers for this night.

Thanks.

[jedijeff]

Did you have any issues?

[ndmuser]

Everything worked fine, no need for LAN Masking. The whole process took under 1 hour.

Thank you for your help!

[jedijeff]

Very good news. Thanks for posting back your results.