Connection issues with FC SAN

[GreyhoundHH]

Hello,

we're having some issues with the SAN connection via fibre channel. Two new ESX 4.1 (cluster #2) servers have been set up and attatched to the same LUNs as our existing servers. These five ESX 3.5 servers (cluster #1) are not having any trouble at all with the SAN.

When I vMotion a VM between the newservers in cluster #2 I get some of the following events:

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Lost access to volume 4aee8864-c13d8a90-471f-001b210e7f11 (LUN9) due to connectivity issues.

Recovery attempt is in progress and outcome will be reported shortly.

Successfully restored access to volume 4aee8864-c13d8a90-471f-001b210e7f11 (LUN9) following connectivity issues.

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What I noticed about the path selection

The ESX 3.5 servers are all set to "Fixed (VMware)", displaying one path as "Active (I/O)" and the other as "Stand by" none of the preferred.

The ESX 4.1servers are set to "Fixed (VMware)", displaying one path as "Active" and the other as "Active (I/O) and preferred.

These settings were set by default and have not been modified by us. Is this just a normal difference between ESX 3.5 and 4.1?

Kind regards

[nkbaumer]

GreyhoundHH,

I was getting the same errors in our logs last week when we found dead paths in our FC storage fabric. You should do a rescan on your hba's and make sure that the paths on your new hosts are all working properly. You didn't mention which type of storage you are using but be sure that your array can support active/active path selection. You might want to try MRU to see if that changes anything.

Take care,

Nick

[GreyhoundHH]

Hi,

thanks for your answer. There are no dead paths and I've alreday rebooted and rescanned the two servers to sort things out.

I've asked our storage team about the multipathing configuration and if the storage array (Hitatchi) supports active-active. I might give MRU path selection a try, but this KB article scares me:

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=101134...

Warning: VMware does not recommend changing the LUN policy from Fixed to MRU, as the automatic selection of the pathing policy is based on the array that has been detected by the NMP PSP.

Kind regards