A lot has changed with vSphere 5.0 and so has one of the most under-appreciated “features”…. VMFS. VMFS has been substantially changed and I wanted to list some of the major changes and express my appreciation for the great work the VMFS team has done!
- VMFS-5 uses GPT instead of MBR
- VMFS-5 supports volumes up to 64TB
- This includes Pass-through RDMs!
- VMFS-5 uses a Unified Blocksize –> 1MB
- VMFS-5 uses smaller Sub-Blocks
- ~30.000 8KB blocks versus ~3000 64KB blocks with VMFS-3
- VMFS-5 has support for very small files (1KB)
- Non-disruptive upgrade from VMFS-3 to VMFS-5
- ATS locking enhancements (as part of VAAI)
Although some of these enhancements seem to be “minor” I beg to differ. These enhancements and new capabilities will reduce the amount of volumes needed in your environment and will increase the VM-to-Volume density ultimately leading to less management! Yes I can hear the skeptics thinking “do I really want to introduce such a large failure domain, my standard is a 500GB LUN”. Think about it for a second, although that standard might have been valid years ago, it probably isn’t today. The world has changed, recovery times have decreased, disks continue to grow, locking mechanisms have been improved and can be offloaded through VAAI. Max 10 VMs on a volume? I don’t think so!