Friday, January 25, 2008

New and interesting features of VI 3.5 - Storage

You know, certainly that VMware released new version 3.5 of their flag product Virtual Infrastructure 3 recently. Let's take a glance what new features it brings and how they can help us in production environment.

As you could use VMware VMotion for hot migration of running virtual machines from one host server to another one, now you are able to migrate the virtual machine's disk from one storage to a second one. The technology is called SVM or Storage VMotion and it is useful in the maintenance period of your primary storage when you need to migrate stored virtual disks to your backup storage without disrupting your running virtual environment. The functionality is still new and you can take advantage of it only via Remote Command Line or RCLI. Until now, we were able to manage a virtual machine via console access or SSH (via ssh connection to an ESX host). RCLI is just another method how to do remote management. Unfortunately, Storage VMotion is available only for fibre channel storages.

The new version introduced support of N-port virtualization for fibre channel SANs which allows to each virtual machine to have its own WWN.

New VI3 supports new hardware as well. In my opinion, the most amazing one is support of SATA devices. It is recommended to check the new IO compatibility guide for supported SATA HBAs. Beside this, VMware includes technical support for InfiniBand (HCAs from Mellanox) and support for 10G ethernet.

The next feature is in experimental phase but I hope it will develop. Until know, multipathing with fibre channel was possible but only in a manner of failover. Now, you can test load balancing based on round-robin scheme.

To achieve better performance in your iSCSI SAN you can set jumbo frames and use TCP segmentation offload.

The last thing which merits our attention is to do VMotion of virtual machines without requirements to have their swap files stored on shared storage. Now, they can be placed locally.

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