Every VMware View implementation has installation hurdles, but View management has its own challenges.
A virtual desktop infrastructure (VDI) relieves the management strain that disparate physical PCs can create. In traditional enterprise-computing models, IT departments must purchase, secure, deploy, monitor and maintain physical machines. In a VMware View infrastructure, however, administrators can centrally manage desktops and tightly control the user experience.
But View management poses its own challenges. Haphazard View management can create numerous problems for IT departments and users. To prevent VDI-related frustrations, watch out for the following View management obstacles.
View management obstacle No. 1: resource usage
In virtual infrastructures, it's critical to monitor resource usage. But it's even more imperative in View deployments, because of its direct effect on users.
Host resources also affect nonpersistent pools, where VMs are usually deleted, recreated and reassigned each time they are used. This configuration creates greater resource overhead because desktops are shutdown, started and logged into more often than virtual server environments. Therefore, resource constraints can lead to major performance issues.
Another resource issue arises when the host's memory is severely oversubscribed. In this situation, unused virtual machines can "page out." Before a new user can connect to a desktop, a VM must deflate the balloon driver -- which can result in connection timeouts and poor performance.
View management obstacle No. 2: storage utilization
Storage requires special attention in View environments, and the effects of VDI on storage arrays are well documented. In short, virtual desktops create a high volume of I/O operations per second, or IOPS, and write operations produce most of the I/O traffic.
Operationally, watch your array performance carefully -- especially during, and shortly after, implementation. Also, make plans to quickly upgrade the storage array should problems occur.
View management obstacle No. 3: provisioning errors
If an error occurs during the provisioning process, the Stop Provisioning on Error pool setting halts the creation of new desktop VMs within a pool. But it can also lead to a pool without desktops.
If this setting is left unchecked, the following scenarios may unfold:
- An environmental problem, such as a data store running out of space, will probably affect every virtual desktop.
- If an error occurs between the VM creation and the VM becoming available, it will result in a worthless (but still running) VM.
Stopping the provisioning process prevents an endless loop of VM deployments, which drains cluster resources.
View management obstacle No. 4: spare capacity
Generally, you want the number of spare desktops at least to equal the number of users that log in within a short time span (usually a few minutes). These reserves ensure that users have an available desktop. You should monitor user-login activity and adjust the settings accordingly.
About the expert
Brian Knudtson is a system engineer at a large Midwestern enterprise technology provider with more than a decade of IT experience. He is a VMware Certified Professional, vExpert and co-founder and former leader of the Omaha-area VMware User Group, and he maintains a VMware-related blog called knudt blog. Follow him on Twitter @bknudtson.
This was first published in November 2010