How to migrate existing ESXi and Windows hosts from FC attached to iSCSI attached

Why not use PowerPath Migration Enabler for the Win2k3 move?  I always prefer PPME, because it's just so darn flexible!

Let us know if that helps!

LUN is a LUN, does not matter how you get to it.  I don't see the need to create brand new LUNs, connect new hosts via iSCSI, add them to the same storage group as current hosts.  Put currents hosts into maintenance mode, unmount datastores, re-connects hosts using iSCSI , add to the same storage group and rescan.

So the same LUN - LUN 100 for example - can be accessed via FC from the existing production host A, and via iSCSI from the new host B on the same array and in the same ESX storage group, can't it?

yes

Great, thank you very much dynamox.

This would be the plan then:

1. Configure four new hosts as part of the existing ESXi cluster. I am not going to zone them to the VNX.
2. Configure the VNX and the new hosts for iSCSI.
3. Configure iSCSI target IP addresses on the new hosts, rescan storage adapters, they will log in and register on the VNX.
4. Put the new hosts in the existing ESXi storage group where I have the FC attached hosts. Rescan storage adapters on the new hosts, they will see all the existing LUNs presented to the existing ESXi hosts.
5. Host vMotion all the VMs to the new ESXi hosts that are iSCSI attached.
6. Put current FC attached hosts into maintenance mode, unmount datastores, remove the FC hosts from the storage group, re-connect these hosts using iSCSI, add to the same ESXi storage group and rescan.

Could you please elaborate more, as far the actual steps are concerned?

Sure.  You can find the PowerPath Migration Enabler documentation on EMC Support.  It clearly breaks down the steps involving in performing a PP Migration.

In simplest terms, you provision new LUNs to your Win2K3 servers, but you do not put a Windows signature on them or format them.  Next, you create a migration handle in the CLI with Powerpath, indicating what source LUN(s) to copy from and what target LUN(s) to copy to.  Then, you enable migration handle, starting the copy process (throttling the copy, if necessary).  Once the data is in sync, you select the target LUN(s) in the migration, meaning, you service your I/Os from the new target LUN(s).  If you're satisfied with the performance, you can commit the migration and unzone the original source LUN(s).

This works only for your Windows hosts, of course, and is not available for the ESX migration.  Also, this would be recommended in a case where you were creating new iSCSI LUNs.

Thanks, but that probably will not work, I am not looking to migrate any data from one volume to another, just changing the type of connection from host to array, the volumes stay the same.

That sounds more like what I need. However, since I have not done this type of migration I have some concerns as to how to do certain steps and not to end up with a server not being able to access the volumes once it is migrated to iSCSI. I need to introduce some details here to make it a bit clearer for myself. I have to migrate two LUNs to iSCSI, which are currently presented to a win2k3 server via FC. The application that is using these LUNs is MS SQL 2005. Below are the steps I intend to follow.

1. Reboot the server to make sure it comes up clean without any hardware or software issues.
2. Identify the services and processes that are using the volumes to be migrates to iSCSI connectivity. I know for sure that SQL is using them. How can I find out what else might be using them, to avoid any windows errors when they are unmounted?
3. Stop SQL services. Stop any other services that may be using the volumes to be migrated. Set the 'Startup type' to 'Manual'.
4. Unmount the volumes to be migrated - how is it done in windows? What shall I pay attention to when unmounting them, so that I can successfully mount them at Step 12?
5. Remove the host from the storage group on the VNX.
6. Remove FC cables from the host.
7. Unregister the host from the array.
8. Configure iSCSI on the host - install the iSCSI initiator, configure iSCSI targets.
9. Reboot the host. When the reboot occurs, it will not automatically mount the volumes that were unmounted in step 4?
10. Make sure the host logs in and registers on the array via iSCSI.
11. Add the host to it's original storage group, from which it was removed in Step 5.
12. Mount the volumes that were unmounted in step 4. How do I make sure that I mount the volumes to use the original drive letters? I currently have two volumes: F and G, identical in size. How do I make sure that the original F is mounted as F, not G, and the original G is mounted as G, not F, so that there are no issues with SQL when it gets started?
13. Start the services that were stopped in step two. Set the 'Startup type' to the original state.
14. Reboot the server to ensure there are no hardware or software issues.

Does this make any sense?

Understood - got hung up on the "move data from FC" in the post title.

Thanks!

Karl