Customers and prospective customers frequently ask “How large should my personal vDisk (PvD) disks be?” The default size is 10GB, but is that too large? Too small?

Of course, the exact recommendation as to how large to size a PvD deployment is customer and deployment specific. However, since PvD is in use internally at Citrix (for some teams), we’ve built up a reasonable characterization as to what a 6 month deployment size consumption might look like. Most users of this deployment that would have been installing applications into their PvD would have already done so, and 6 months of usage is likely sufficient time to populate the PvD with a representative sample of the types of data and applications a particular user might install.

Before I give the numbers, a few notes:

1. These PvDs have been deployed for 6 months, since our 5.6.5 PvD release was shipped.

2. The users using this PvD pool are (typically) engineers, testers, and others in the development community. I don’t have access to the PvD metrics for other teams.

3. Only 2 of 81 users asked to have their PvD size increased from the default 10GB to a larger amount. One user has 20GB allocated and has used 53% of that space. The other user is myself, with a 40GB PvD, which I mainly use for stress testing what happens when PvDs approach capacity. I’d probably discount mine as an unrealistic statistical outlier.

Of the remaining PvDs in use in our internal deployment, the average used space is 36.74%, meaning on the average each user has consumed 3.674GB of data in their PvD (max size 10GB). This size includes both the user profile as well as any changes accumulated in the PvD (app installs, etc) since the pool was deployed approximately 6 months ago. The highest capacity was over 90%, and the lowest was 9%. This reflects the amount of space provisioned by the hypervisor over the course of the past 6 months in the PvD, so this might actually be more than what users actually are storing presently.

We also have been internally testing PvD with our upcoming Excalibur build. Obviously, this PvD pool is much newer (only a few weeks old). In this pool, the PvD usage is approximately 18% (1.8GB). It would appear that PvDs populate a few GB up front (most likely user profile data), then slowly accrete changes up to the aforementioned level over time. As many of you know, PvDs capture all changes occurring in a machine, so it would certainly be possible that these numbers would creep upward past 36%, but based on a 6 month usage pattern, it seems that less than half of the available space is used by a typical user.

It will be interesting to come back to this metric in another 3-6 months and see if that assumption holds true, or if the PvD space usage plateaus over time.