This feature – virtual SAN, also known as VSAN – can help administrators eventually eliminate or reduce their reliance on what can be costly storage arrays by harnessing together all of the local solid state storage and hard disk drives present in the vSphere servers and presenting it as a storage pool to the cluster. VSAN leverages the solid state storage on local servers as a read cache, which accelerates the hard disks, thus increasing overall storage performance. There is a lot more to VSAN that I will discuss in future articles. Suffice it to say that VSAN has the potential to be a data center game changer.
While VSAN is an important step forward in the evolution of the data center, vSphere 5.5 also has some improvements to the more traditional storage features in the product:
- vSphere 5.5 increases the maximum size of VMDK files from around 2 TB to 62 TB. The same applies to raw device mapped volume.
- In previous editions of vSphere, Fiber Channel either didn’t or couldn’t operate at the full 16 GB speed available in the standard. In vSphere 5.5, these limits are gone and organizations can enjoy full end-to-end support for 16 GB Fiber Channel.
- Those using Microsoft Cluster Services in vSphere-based virtual machines now have more stability and interoperability options, including support for Windows Server 2012, round robin pathing, and support for both iSCSI and Fiber Channel.
- When a host suffers a storage device failure, vSphere 5.5 can use a new feature called PDL AutoRemove to ensure that future I/O requests are not targeted at these devices.
These are just some of the storage enhancements found in vSphere 5.5. There is much more in the released product.