Switching Falconstor IPStor to use 1 to 1 mapping for LUN assignment

Switching your Falconstor IPStor server to use 1 to 1 mapping from any of the other avaliable mapping options Like All to All or All to 1 can be an annoying task, but if you have VMWare ESX or ESXi and have VMotion you can do this with 0 down time and Ill show you how. These steps will assume you are NOT in a fail over cluster with Falconstor

In my example I am using 2 ESX 4.1 hosts. Monster01 and Monster02. Each one of my hosts is designed to support running all our virtual machines from so moving all the vms to a single host like this is not going to have a negative impact on any vm and users will never know this is going on.

First Im going to need to vmotion all the machines to a single host. I move all the virtual machines running on Monster01 to the host Monster02. Once this is done I put Monster01 in maintence mode, then shut it down. This step is only needed if you are SAN booting your ESX/i host and need to change the LUN the ESX/i OS is running on.

Once its shut down comes the hard part if no one ever documented what WWPN is used for what. If that is the case for you like it was for me then you can figure this out by looking at your physical adapters and finding all the adapters that are in target mode. Write down the WWPN of each one. You might have a bunch.. Thankfully I only had 2 adapters in terget mode that were online. Yay!! a 50/50 chance of getting it right on the first try! I took LUN 0 which has my ESX 4.1 install on it and did a 1 to 1 map. On the ESX host this was simple since we only had 1 adapter plugged in and configred. Next I had to take a shot in the dark because our cables are a mess and no one documented what WWPN was used for what. I got it wrong the first time because once I assigned the LUN and turned the host back on the box failed
to boot. I switched to my other choice and Bam it booted!

Next to quickly switch the other 40 LUNS I went to the Falconstor management console and went into the SAN Clients and selected Monster01 I right clicked on each LUN and selected properties. From here you can switch from your current mapping to 1 to 1 using a select box. You will get a warning about data transmission stopping when you do this. That is fine since there are no running virtual machines on Monster01 (remember its still in maint mode) Next you select the 2 WWPNs needed for the initiator (the ESX host) and the target (the Falconstor server). Once you have completed this for all LUNs you can bring the ESX host out of maint mode and VMotion the machines from Monster02 to Monster01 and then repeat this process on Monster02.