Migrating iscsi volumes to datastores - vmware

Spammeh

Spammeh

Spammeh

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I have a bit of a bizarre question, but hopefully you guys can help. I currently have a vmware exchange 2003 server whcih has 6 disks

2 of which are additional hard drives configured within vsphere and there are 4 attached via MS iSCSI initiator directory to the SAN via iqn.

What I want to do is migrate these 4 initiator drives to be attached just like the other 2, however of those drives, 2 of them contains the MS Exchange mailstores.

Is it as simple as adding these SAN volumes to vsphere as datastores and attaching them to the vm? Or will it wipe those volumes when creating them as a datastore
 
Be careful with your terminology. Do you actually want to create a datastore or are you wanting this to end up as an RDM?

What exactly are you trying to achieve, why do you want to do this?
 
The idea behind this is that the existing SAN is being disposed of, we have a replacement in place but unlike the rest of the estate its not a matter of just migrating the disks using storage vmotion within vSphere.

I'm not quite sure why they are attached via iSCSI initiator instead of via vsphere as additional disks (I assume for performance). Its not even set up currently as an RDM, simply bypassing vmware completely and connected directly to the SAN.

I'm not too bothered whether these disks are attached via the 'standard' vsphere method, or via RDM, but if I go via VMFS volumes how am I going to get them from this soon-to-be-decommisioned SAN to my new one with little downtime?
 
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Had another read around, is this the recommedend process?

1. Remove iSCSI initiator volumes and attach SAN volumes via RDM to virtual machine
2. Run some convertor mechanism within vsphere to convert from an RDM to a VMDK?
 
Spammeh said:
Had another read around, is this the recommedend process?

1. Remove iSCSI initiator volumes and attach SAN volumes via RDM to virtual machine
2. Run some convertor mechanism within vsphere to convert from an RDM to a VMDK?
Click to expand...
That's pretty risky. If you have enough spare capacity on the SAN, you should either present a new LUN to VMware and create new VMDKs for the Exchange box, or present new RDM LUNs to the Exchange VM. Then do some sort of offline copy of the contents of the drives (from the iSCSI drives to the new drives). You now have two complete copies of the data (at this point you haven't touched the data on the iSCSI drives). You then remove the iSCSI drives, re-letter the VMDK/RDM drives to have the same drive letter as the iSCSI drives used to have, and Exchange should work.

I am generalising; obviously you have to be very careful when playing with Exchange databases. There will be a process to follow, but I hope you get the gist of what I'm suggesting...
 
I've done similar but really you're in a risky position.

Honestly, I'd treat this as a DB migration effort - create the new LUNs, get them mapped to the guest OS and migrate the DBs to them before decomming the old LUNs/SAN.

P.S. using the MS iSCSI initiator inside a VM is risky business (especially if vMotion is involved) and pretty much magnified by the fact that Exchange is involved...
 
DRZ said:
P.S. using the MS iSCSI initiator inside a VM is risky business (especially if vMotion is involved) and pretty much magnified by the fact that Exchange is involved...
Click to expand...

+1 been there, got the all nighter tshirt
 
I'm aware that its not an idea situation, this is a server thats been set up a long time, long before I stepped foot inside this place!

Is it as simple as copying the files from one volume to another and then changing the drive letters to match with Exchange 2003 or will it throw a wobbly?
 
Note Only assign permissions to the Server Operators group if the Exchange server is a domain controller. Otherwise, assign permissions to the Power Users group. Only domain controllers should have permissions to the built-in Server Operators group. Stand-alone and member servers should have permissions to the built-in Power Users group.
Click to expand...

Don't ever miss that. I spend 2 days for this issue only to have missed that one.
 
In your situation I would do the following

Leave the current MS iSCSI drives connected.
Mount new VMWare disks in your exchange server
Create new exchange databases on the new disks
Use the Exchange management tools to bulk move mailboxes to the new databases.

Done this before and doing that way in theory result in no downtime to the end users, plus its more of a managed move

Kimbie
 
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