No one doubts that virtualization has made managing centralized storage environments far easier than managing an equivalent mass of physical SAN-attached servers. But as businesses spin up new VMs and create data at breakneck speeds, the limitations of VMware's VMFS3 clustered file system have often yielded complex, hard-to-manage storage configurations.
Thankfully, with vSphere 5, VMware has upgraded the file system with a number of substantial improvements. Although some lmitations remain, the new VMFS5 file system provides both greater scalability and easier management.
Bigger and badder
The most visible change in VMFS5 is an increase in the maximum VMFS volume size from 2TB to approximately 64TB. In older versions of vSphere (and VMFS), you'd need to provision a series of partitions, or extents, that would be concatenated together to form a volume of up to 64TB using 32 separate SAN volumes, each containing a 2TB extent.
I've never actually seen this in real life with VMFS3, mainly because it's an excellent way to turn your storage administrator into an alcoholic overnight. Instead, most shops simply deploy a mass of 2TB VMFS volumes and spread the VMs out across them. This makes your storage admin slightly less likely to hit the bottle, but it's less capacity efficient and just spreads the management headache across the virtualization and storage admin, rather than decrease it in any meaningful way.