VMware vSphere 5: The Future of Virtualization Storage

The upcoming release of VMware vSphere 5 brings with it a plethora of exciting new features and improvements, but one that stands out in particular is the upgraded version of the VMware vStorage VMFS volume file system. With VMFS-5, VMware has addressed one of the limitations of its predecessor, VMFS-3, which restricted the maximum size of VMDK files based on the block size defined during datastore formatting.

The issue with VMFS-3 was that the block size determined the maximum size of VMDK files stored on the datastore. This meant that when planning your datastore infrastructure, you had to have a clear idea of how large your VMDK files might potentially be during the lifecycle of the datastore. For VMFS-2 and VMFS-3, the block sizes and their impact on VMDK files looked like this:

[table id=2 /]

As you can see, if you formatted your datastore with a 1MB block size, the maximum VMDK file size would be limited to 256GB. While this may not be a significant issue for small to medium-sized environments, it could prove to be a real headache for larger ones with limited storage space.

Thankfully, VMware has eliminated this limitation in VMware vSphere 5 and VMFS-5. The new unified block size is now 1MB, and the limits on VMDK file sizes are completely removed. In fact, the block size no longer really matters, as there are no longer any limits to worry about.

Here’s a simplified table for vSphere 5 and VMFS-5:

[table id=3 /]

Upgrading from VMFS-3 to VMFS-5 is an online and non-disruptive upgrade operation, which means you can perform the upgrade while your VMs are running on the datastore. Additionally, you can extend VMDK files to the new limits on an upgraded VMFS-3 datastore, as long as it has been upgraded to VMFS-5.

Note that in order to take advantage of these new features and improvements, you’ll need to update all your hosts to vSphere 5 before upgrading your datastores. This is because vSphere 4 (and earlier) can’t read the new VMFS-5 filesystem.

This simplification of VMDK file sizes is a welcome change for vAdmins, as we no longer have to worry about block size limitations when planning our virtualization storage infrastructure. Of course, there are other improvements in VMFS-5 as well, but we’ll save those for future posts.

In conclusion, the upgraded version of the VMware vStorage VMFS volume file system in VMware vSphere 5 is a significant improvement over its predecessor, VMFS-3. With the elimination of VMDK file size limitations and the simplified table for block sizes, vAdmins can now focus on other aspects of their virtualization storage infrastructure. We’re excited to see how this new feature will impact your virtualization environments!