vSphere 5.5 Storage Enhancements Part 1: 62TB VMDK

Regular readers will know that I’ve spent a lot of time recently posting around VSAN. But VSAN wasn’t the only announcement at VMworld 2013. We also announced the next release of vSphere – version 5.5. I now want to share with you a number of new storage enhancements which we have made in this latest release of vSphere. To begin with, we will look at a long-awaited feature, namely the ability to have virtual machine disk files that are larger than 2TB, the traditional maximum size of VMDKs.

Although we have introduced the new VMDK size, for the most part Virtual Machine behavior is unchanged. You can still do snapshots, suspends, migrations, etc, with this new size, but there are some considerations to take into account. I’ve listed them here:

What is supported?

What is not supported?

 Web Client Support Only

For some time now, VMware has made it clear that all new features/enhances supported via the vSphere web client. This is also true for the the new larger 62TB VMDKs. If you create a large VMDK via the vSphere web client, and then try to examine its properties via the C# client, you will see the following ‘out of range’ error:

Note that you will not be able to create the larger VMDKs with the C# client – you will have to use the web client. If you log onto an ESXi 5.5 host using the C# client, a warning is now displayed about 5.5 features only being available via the vSphere web client.

While we readily admit that a number of products such as VUM (vSphere Update Manager) and SRM (Site Recovery Manager) still need integration into the web client, this is underway and customers should familiarize themselves as much as possible with the web client.

What about non-passthru RDMs?

We have supported 64TB pass thru RDMs (physical compatibility mode) since vSphere 5.0, the same time we introduced a 64TB VMFS volume on a single LUN. With the release of vSphere 5.5, we also have support for very large non-pass thru RDMs (virtual compatibility mode). These vRDMs in vSphere 5.5 can now assume the same size as a VMDK (~62TB).

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