Last year with version 5.1, VDI-in-a-Box introduced the ability to take advantage of two separate data stores, allowing VDI-in-a-Box to better leverage the direct attached storage of servers.  When using the Hyper-V or ESX hypervisors, VDI-in-a-Box allows you to define a second datastore to separate the storage of golden images, and linked clones.  Now with version 5.2 of VDI-in-a-Box we have introduced the option for a third datastore. In addition to the datastore options for golden images and desktops, there is now an option to store the personal vDisks associated with personal desktops on a separate datastore.  Administrators now have the ability to store images, desktops, and personal disks separately or together on the datastore of their choosing. Best of all, this option is available on all supported hypervisors.

Upon initial configuration, the vdiManager uses a single datastore. This primary datastore contains all of the golden images, desktop instances, and the vDisks associated with Personal Desktops.  Enabling the multiple datastore feature in vdiManager’s advanced properties makes it possible to separate these three types of data onto their own data stores.

The flexibility of multiple datastores can be leveraged by storing pooled desktops on an SSD datastore for improved IOPS performance.  Since pooled desktops require much less space, better IOPS performance can be achieved by adding only small amounts of SSD drives to a server.  Using SAS drives for the primary datastore will provide higher capacity storage for storing the larger golden images.  Using both SAS and SSD storage in the servers allows VDI-in-a-Box to avoid being constrained by the IOPS limitations of SAS drives, or the small capacity of SSD drives. With this combination of IOPS and storage space, administrators can pack more desktops than ever on each server in the VDI-in-a-Box grid.

The third datastore option for personal disks allows the administrator to place the PvD on either SAS or SSD datastores. If there will be a lot of personal desktops and the personal disks will take up a large amount of space, it may be advisable to place them on the SAS drives. If there are not many personal desktops in an environment, and they do not take up a significant amount of space, they can be placed on the SSD datastore for improved read and write performance.  Another option when running the VDI-in-a-Box environment on Hyper-V 2012 or ESX hypervisors is to configure the personal disk datastore to use shared storage.  Doing this creates the additional benefit of allowing personal desktops to survive a server failure without the need for manually backing up and restoring the personal disks. In this scenario, each server in the VDI-in-a-Box grid would be configured to use the same shared storage to hold personal disks. When any server is hosting a personal desktop, the personal disk associated with that desktop would be stored on disks that can be read by all servers in the grid.  In the event that the server hosting a personal desktop were to fail, a new desktop can be spun up on a running grid server and that new desktop can be reattached to the same personal disk because it is being read from shared storage.

To find out more about how using multiple datastores can improve performance, run more virtual desktop per server, and enhance high availability of personal desktops, please see the following reference links:

http://support.citrix.com/article/CTX136080

http://www.citrix.com/tv/#videos/7397