Think desktops and a few concerns that come to your mind instantly are hardware refresh cycles, patch management and endpoint security. While virtual desktop infrastructure (VDI) technology is a cost-effective solution to these issues, a VDI technology implementation gone wrong
For instance, with the centralized nature of VDI, an outage at the server running the VDI technology can result in complete unavailability of desktops.
When we looked at implementing VDI technology in 2008, we were one of the first ones to do so. At this point we did not have enough local examples from the industry to learn from. Therefore we followed a well-planned and a phased approach to avoid a failed VDI technology deployment.
Here are a few things (that when not taken care of) can result in a failed VDI technology implementation.
Taking the big bang approach with VDI technology
Do not try and implement desktop virtualization across the board. VDI technology may not be the answer to all desktop management woes. It may not be the right solution for certain type of users. Take a phased approach with the VDI technology implementation.
In the first phase we moved a few internal users to the virtual desktop environment. In the next phase we moved remote users on to VDI technology implementation. We have a certain section of users using AutoCAD, which is a resource intensive application. During the implementation phase, we realized that implementing AutoCAD in an infrastructure running on VDI technology was not feasible.
The application then was not built to run well in a virtual desktop environment. Hence we did not extend the use of the VDI technology implementation to these users and had them running on a non-virtualized desktop environment.
Under-sizing of resources
Under-provisioning resources can result in a degraded desktop experience for users or can simply congest the resource pool of a VDI. At worst it could bring down the VDI technology implementation. When allocating virtual desktop resources to users, one needs to determine the type of users, their number, the type of applications that they use and the amount of desktop resources consumed by them.
At the implementation stage we had allotted storage space of 5 GB per user. However, further into the VDI technology implementation, we found out that storage requirements for users varied and hence we had to re-allocate storage space accordingly.
We also had to implement solutions to increase bandwidth utilization. When we tested the virtual desktop environment for remote users, we realized that applications with higher response times (in milliseconds) required more bandwidth as the number of users per site grew by five more than those we had provisioned for. To resolve this issue, we installed WAN optimization solutions from Citrix. Increasing the bandwidth would have increased the recurring cost.
Had we not taken these steps, application response times would have been lower. Users would have run out of storage soon and trying to salvage the situation post implementation would have been tedious. It would have affected the overall performance of the virtual desktop infrastructure. The whole idea of deploying the VDI technology would have then been in vain.
Also resource utilization thresholds for the virtual desktop infrastructure should preferably be set to around 60%. That way the IT team is notified early when VDI technology implementation reaches its thresholds, instead of say at 90% percent where the chances of service unavailability due to a deadlock is higher.
Not having a backup infrastructure in place
Since a VDI technology implementation means a centralized infrastructure, it is absolutely necessary to have backup infrastructure in place to avoid downtime. However just having a backup infrastructure in place is not enough. The readiness of this infrastructure has to be monitored and tested on a regular basis.
In our case, we had a dedicated person deployed to monitor the backup infrastructure in test environment. He would test the readiness of backup copies of infrastructure running on VDI technology, to see if we can recover from a disaster.
About the Author: Basant Kumar Chaturvedi is the Controller IT (IT Head) at Perfetti Van Melle India. Chaturvedi has over 18 years management and implementation experience in Enterprise IT.
(As told to Harshal Kallyanpur)
This was first published in February 2011