victory_is_mine
3 Argentium

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

Hi All,

I am looking for the best ways to achieve the following - migrate existing ESXi and Windows 2003 hosts from FC attached to iSCSI attached, migrate data from the FC connected VNX LUNs to iSCSI connected VNX LUNs.

Here is what I am currently working with:

  1. Four existing ESXi 5.5 hosts configured in a VMware cluster. Two standalone Win2k3 hosts. Host are UCS B200.
  2. One VNX5200.

These four ESXi hosts are connected to the VNX via FC.

We are introducing four more B200 hosts, and want to connect them to the same VNX via iSCSI, and migrate the existing FC LUNs to the new iSCSI LUNs.

What I thought I can do for the ESXi is this.

  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, the existing hosts and the new hosts for iSCSI. I need the existing hosts to see the iSCSI LUNs so that I could move the VMs to them. I am not sure how to deal with the existing hosts. They are already logged in and registered  on the VNX via FC and they are in the storage group for ESX hosts, so how do I register them via iSCSI, if I have to do that at all?
  3. Connect the new hosts to the VNX via iSCSI, they have to be logged in and registered.
  4. Put the new hosts in the existing ESXi storage group where I have the FC attached hosts. If I do that, will they see the FC attached LUNs? I assume they would, as the storage protocol - FC or iSCSI - should not matter here, as I am accessing different LUNs via different protocols, not the same LUN via two protocols (FC and iSCSI), which is not supported.
  5. Configure the new LUNs and put them in the existing ESXi storage group. I am not quite clear on this either: the new hosts will see the new LUNs via iSCSI, as this will be the only protocol configured for them. However, how will the existing ones see them - via FC or via iSCSI? How do I make sure that the existing hosts see the new LUNs via iSCSI only, if that is at all possible?

On the windows side I am planning on following the same strategy, except I am not adding any new hosts, just moving the existing ones from FC to iSCSI, and I have to install iSCSI initiator. However, the questions remain the same:

  1. They are already logged in and registered  on the VNX via FC and they are in the storage group for ESX hosts, so how do I register them via iSCSI, if I have to do that at all?
  2. How do I make sure that the existing hosts see the new LUNs via iSCSI only, if that is at all possible?

Appreciate your input.

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umichklewis
4 Tellurium

Re: How to migrate existing ESXi and Windows hosts from FC attached to iSCSI attached, move data from FC connected VNX LUNs to iSCSI connected VNX LUNs

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!

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Highlighted
dynamox
6 Thallium

Re: How to migrate existing ESXi and Windows hosts from FC attached to iSCSI attached, move data from FC connected VNX LUNs to iSCSI connected VNX LUNs

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.

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Highlighted
victory_is_mine
3 Argentium

Re: How to migrate existing ESXi and Windows hosts from FC attached to iSCSI attached, move data from FC connected VNX LUNs to iSCSI connected VNX LUNs

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?

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dynamox
6 Thallium

Re: How to migrate existing ESXi and Windows hosts from FC attached to iSCSI attached, move data from FC connected VNX LUNs to iSCSI connected VNX LUNs

yes

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victory_is_mine
3 Argentium

Re: How to migrate existing ESXi and Windows hosts from FC attached to iSCSI attached, move data from FC connected VNX LUNs to iSCSI connected VNX LUNs

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.
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victory_is_mine
3 Argentium

Re: How to migrate existing ESXi and Windows hosts from FC attached to iSCSI attached, move data from FC connected VNX LUNs to iSCSI connected VNX LUNs

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

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Scott Riley
2 Iron

Re: How to migrate existing ESXi and Windows hosts from FC attached to iSCSI attached, move data from FC connected VNX LUNs to iSCSI connected VNX LUNs

The concept is the same for the Windows standalone hosts.  I would unmount the volumes on the host, then remove the host from the storage group on the VNX.  Then configure iSCSI on the host.

I would prefer to do a reboot on the host at this point to clean things up.  Then create a new host on the array with the new iSCSI initiators, then add that host to the storage group.  At that point you can mount the volumes, and all IO will be going across iSCSI.

I don't think PPME is a good option here, you are just changing the IO path to the array, not actually migrating data...

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Highlighted
umichklewis
4 Tellurium

Re: How to migrate existing ESXi and Windows hosts from FC attached to iSCSI attached, move data from FC connected VNX LUNs to iSCSI connected VNX LUNs

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.

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victory_is_mine
3 Argentium

Re: Re: How to migrate existing ESXi and Windows hosts from FC attached to iSCSI attached, move data from FC connected VNX LUNs to iSCSI connected VNX LUNs

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?

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