Comments on: Microsoft Adds Quick Storage Migration Feature to SCVMM

By: Dracolith

Dracolith — Fri, 26 Jun 2009 17:44:50 +0000

That would work great for completely stateless servers, e.g. DNS servers, web servers, and proxies that don't have any local databases or session files stored on them (any VM that doesn't hold critical data).

Otherwise, the problem is data loss between the time you started the clone operation and the time you powered off the old VM.

Lets say you have an Exchange Server VM.
(1) You start the hot clone
(2) An e-mail comes into your exchange VM and is stored in Joe's mailbox
(3) The hot clone finishes
(4) You power off the original VM and power on the new one.

Joe has lost the new e-mail message that arrived, the sending mailserver won't re-send, because the original Exchange VM already acknowledged succesful delivery of the message.

Matters are more severe if the VM is a domain controller in a multi-DC environment, replication can be seriously messed up. If the VM is running a SQL server for a financial application, or the backend for an e-commerce app, you can lose transactions or orders.

By: Dracolith

Dracolith — Fri, 26 Jun 2009 11:44:50 +0000

That would work great for completely stateless servers, e.g. DNS servers, web servers, and proxies that don't have any local databases or session files stored on them (any VM that doesn't hold critical data).

Otherwise, the problem is data loss between the time the clone started and the time you started the clone operation and the time you powered off the old VM.

Lets say you have an Exchange Server VM.
(1) You start the hot clone
(2) An e-mail comes into your exchange VM and is stored in Joe's mailbox
(3) The hot clone finishes
(4) You power off the original VM and power on the new one.

Joe has lost the new e-mail message that arrived, the sending mailserver won't re-send, because the original Exchange VM already acknowledged succesful delivery of the message.

Matters are more severe if the VM is a domain controller in a multi-DC environment, replication can be seriously messed up. If the VM is running a SQL server for a financial application, or the backend for an e-commerce app, you can lose transactions or orders.

By: Joel

Joel — Fri, 26 Jun 2009 04:55:50 +0000

Exactly, W2k8 R2 (RC2) is in some kind of beta, not released yet.
This just shows that MS is way behind VMW and they know about it!

By: rbrambley

rbrambley — Fri, 26 Jun 2009 02:25:58 +0000

LOL. Isn't it understood that marketing is supposed to be self serving? The QSM vs SVMotion table is definitely leaning towards Redmond, WA. No doubt!

What if you hot clone a VMware VM to a new storage location, and then power off the original and power on the new VM (essentially like QSM). Then you could match both technologies row for row. No?

By: rbrambley

rbrambley — Fri, 26 Jun 2009 02:17:58 +0000

Joel,

You have a point with the proven -ness (couldn't think of a better word) of VMware SVMotion. However, MS has come a long way quickly with the ability to use a clustered file system and shared storage, and now has an answer for automated storage migration. Will the first version be acceptable? We'll see.

As Dracolith points out both W2K8 R2 SP2(containing Hyper-V) and SCVMM R2 Release Candidate are available now and together provide a working, but not final, version of QSM.

By: Dracolith

Dracolith — Fri, 26 Jun 2009 01:27:42 +0000

You can get W2k8 R2.

I agree comparing against VI3 instead of vSphere seems like a self-serving comparison choice.

By: Joel

Joel — Thu, 25 Jun 2009 20:02:10 +0000

Hmm, that comparison is really screwed up..
To compare a MS product that is not yet released to an VMW product that is a generation old???

How about compare the latest products that you actually can get? (W2k8 vs vSphere4)