I recently got a great email from an IBMer in the Netherlands by the name of Jack Tedjai. He sent me two screen shots, taken with the new performance monitor panel (that comes with the SVC and Storwize V7000 6.2 code). He wrote:
I am working on a project to migrate VMware/SRM/DS5100 to SVC Stretch Cluster and one of the goals is to prevent using ISL (4Gbps) and VMware Hypervisor/HBA load during the migration. For the migration we are using VMware Storage vMotion. To minimize the impact of the migration on production, we tested VAAI for Storage vMotion and template deployment and it worked perfectly.
So whats this all about? Well one of the improvements provided with VAAI support is the ability to dramatically offload the I/O processing generated by performing a storage vMotion. Normally a storage vMotion requires an ESX server to issue lots of reads from the source datastore and lots of writes to the target datastore. So there is a lot of I/O flowing from ESX to the SVC, and then from the SVC to its backend disk. What you get is something that looks like the image below. In the top right graph we have traffic from SVC to ESX (host to volume traffic). In the bottom right graph we have traffic from the SVC to its backend disk controllers (DS5100 in this case). This is SVC to MDisk traffic.
When we add VAAI support to the SVC, we suddenly change the picture. Suddenly VMWare does not need to do any of the heavy lifting. There is almost no I/O between VMWare and the SVC (no host to SVC volume traffic) related to the vMotion. The SVC is still doing the work, but it is happening in the background without burning VMWare CPU cycles or HBA ports (in that there is still SVC to MDisk traffic).
This difference translates to: Faster vMotion times, far less SAN I/O and far less VMware CPU being used on this process.
So do VMware support this? They sure do! Check this link here. It currently shows something like this (taken on June 23, 2011):
So what are your next steps?
- Upgrade your Storwize V7000 or SVC to version 6.2 code. Download details are here.
- Download and install the VAAI driver onto your ESX servers. You can get it from here. If your already using the XIV VAAI driver you need to upgrade from version 126.96.36.199 to version 1.2. There is an installation guide at the same link.
And the blog title? It means friendly greetings in Dutch. So to Jack (and to all of you), vriendelijke groeten and please keep sending me those screen captures.