vSphere APIs for IO (VAIO) Filtering is finally here to stay

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VMware committed and continued to work on the API’s for IO filtering for a long time now. This very interesting feature was originally announced last year at VMworld 2014 back together with VVOLs and was expected to be released together with vSphere 6 and really got my interest back then. Where Virtual Volumes (VVOLs) was finally released in vSphere 6. The VAIO part was still not yet there. This piece of the puzzle was “just not  yet’ finished. Some vendors currently make illegal use of kernel  hooks to get into the data path of the hypervisor. Where this new piece of software will finally allow other vendors to properly hook up in the correct “supported” data service path.

What is VAIO?

VAIO enables secure filtering of a VMs IO safely in the kernel according to a policy. First use-cases are caching and replication. The service is storage agnostic to different architectures.



VAIO will add value to VVOL, Virtual  SAN and works with all other VVOL enabled legacy storage.

There are of course other possibilities:

  • Encryption
  • De-duplication
  • Tiering
  • Analytics

I’m hoping to see Virtual SAN making use of some possibilities above soon.

The IO Path with a Filter

The IO filter actually lives in the VM user world where the framework is completely kernel based. The VAIO framework detects a filter policy and executes the filter against the IO. The IO return directly to be committed to the physical device.



VMware will have 5 partners ready for VAIO at the end of 2015. Design  partners Sandisk and EMC where heavily involved and will be the first to launch their products with VAIO support.

Interestingly, vendors like PernixData and Zerto are not on this list, which is very interesting as they make heavily use of the current kernel hooks.



My Take

VAIO is a great idea and there will be lots of uses for this new feature. It took an awful long time for VMware to get it finished. New storage services like VVOLs and VMFS6 must have made things much more complex. I’m going to be visiting SanDisk at VMworld to get more information about how they use VAIO to get their caching solution hooked in the VMware kernel. More soon.