Better VM storage management with VMware vVOLs

The next step in the storage integration after vSPhere API for Array Integration (VAAI) and VSphere Storage APIs for Storage Awareness (VASA) will be the VM Volumes or vVOLs.

A vVOL is a VMDK stored natively inside the storage system. The concept of vVOLs helps to eliminate the problem of VM storage management granularity, when tens of VMs are stored inside one LUN/VMFS Datastore, and the snapshot/replica/remote replica creation/restore operations can be performed by the storage system only on the LUN/Datastore level.

There are three objects composing the vVOL technology:

• Storage Provider – allows the storage system capabilities to be recognized and used by vCenter using VASA
• Protocol Endpoint – the I/O de-multiplexor device which will exist on a storage system and will represent a logical I/O channel from the ESXi hosts to the entire storage system
• Storage Container – the capacity pool on the storage system

Here’s an overview of the vVOLs feature

And a demo showing several things using vVols and HP 3PAR

Please take note that the vVOL feature is still a technology preview and is not available in VMware and HP products.

And the vVOLs should be supported only for the  block level protocols such as FC and iSCSI. Does it mean that this feature will  weaken the NetApp positions – the major NFS player on the storage market???     

Storage for VMware - VAAI Capability

Choosing the storage array for VMware, except base compatibility, which can be checked in VMware Compatibility Guide (Storage/SAN), is also useful to understand is storage system VAAI capable or not.

VAAI (vStorage APIs for Array Integration) is a feature in ESX/ESXi 4.1 and later versions that provides hardware acceleration functionality. It enables your host to offload specific virtual machine and storage management operations to compliant storage hardware. With the storage hardware assistance, your host performs these operations faster and consumes less CPU, memory, and storage fabric bandwidth.

Now VAAI includes the following primitives:

• Blocks Zero is a communication method for thin provisioning capable storage arrays, allowing them to quickly zero out storage capacity for later reclamation. 
• Full Copy commands the storage array to make a mirror or snapshot of data without any I/O on the server hardware.
• Hardware Assisted Locking enables more granular control of shared storage resources in ESX clusters.
• Thin Provisioning allows an ESXi to tell the storage array that space that was occupied by a VM (whether it is deleted or migrated to another datastore) can be reclaimed. This allows an array to correctly report space consumption of a Thin Provisioned datastore, and allows customer to correctly monitor and correctly forecast new storage requirements.

Using VAAI can make significantly easier the VMware storage resources administration. The Full Copy primitive is very important when frequent VMs or datastores snapshots are required (usually to provide low RPO value).

And don’t forget to check the availability of VMware plugin for storage system administration.