In this post, I want to highlight a number of storage improvements made in vSphere 5.1 that are going to be leveraged by the next release of vCloud Director.
First off, we have the new file sharing scalability enhancements made in VMFS-5, which now allows up to 32 hosts to share a single file. This is covered in detail in part 1 of this vSphere 5.1 storage enhancements series of blog posts, but what this does mean for vCloud Director is that vApps deployed on linked-clones can now have many more hosts sharing the base disk on a VMFS-5.
VAAI NAS Offload
Sphere 5.0 introduced the offloading of linked clones for VMware View to native snapshots on the array via NAS VAAI primitives. You can read more about this here. vSphere 5.1 NAS VAAI enhancements will allow array based snapshots to be used for vCloud Director vApps based on linked clones, in addition to being used for VMware View.
Just like VAAI NAS support for VMware View in vSphere 5.0, this feature will also require a special VAAI NAS plug-in from the storage array vendor.
At the time of writing this article, NetApp already have this feature included in their next VSC release (4.1) which is currently in beta.
If “Fast Provisioning” is used on the Org vDC Storage settings AND the check box “Enable VAAI for fast provisioning” on the overall system Datastore settings is selected, it will trigger the right commands to use a native array-based snapshot for a linked clone instead of a standard redo log based one.
Profile Driven Storage Interoperability with vCloud Director
Storage Profiles are now represented in vCloud Director. Storage Profiles still must be configured from the vSphere layer, but they now surface up into vCloud Director. The storage profiles must first be added to a Provide vDC. For example, you might have Gold, Silver & Bronze storage profiles created. This then allows storage to be allocated and managed on a per ORG vDC. Again, continuing our example, this organization can only use datastores which are tagged as ‘Silver’. This support for Storage Profiles allows a high level of seperation between organizations at the storage level. Below is a snapshot of an ORG vDC with two storage profiles, one for iSCSI storage and one for NFS storage.
If the Storage Profile associated with a vApp is changed (this can be done via the properties of a vApp), the vApp is automatically Storage vMotion’ed to a compliant datastore. It is great to see vCloud Director leveraging this excellent vSphere feature.
Storage DRS Interoperability with vCloud Director
One of the major enhancements in vSphere 5.1 is to provide interoperability between Storage DRS and vCloud Director. This essentially means that vCloud Director 5.1 now recognises datastore cluster objects from Storage DRS. Just like Storage Profiles, the configuration of Storage DRS is done at the vSphere layer, but the resulting datastore clusters and their respective configuration surface up into vCloud Director. In order for this interoperability to work, Storage DRS now understands linked clones (which it didn’t do previously). Going forward, vCloud Director can now use Storage DRS for initial placement, space utilization and I/O load balancing of vApps based on linked clones.
Although this might be considered a minor improvement, it does alleviate some additional administration which was necessary in previous versions of vSphere/vCloud Director.
I guess the next question then is how do you tell if you have a snapshot on the VM?
By default this information is not displayed on the Virtual Machine view. To show this information, select the option to display the Column headings which is on the right of the screen. Place a tick in the Snapshot column. You will now have a column denoting whether or not there is a snapshot for the Virtual Machine as per the diagram below,
It is nice to see these vSphere storage features being leveraged by vCloud Director. It’s especially nice to see some of the interoperability between products and features.
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