If your VDI users march to the beat of their own drums, then you need unique user profiles to keep them marching -- and working.
When you deploy virtual desktops, one of the biggest considerations is user personalization. Will users be able to change their own settings? How much will administrators control? What kind of user profiles will you implement, and where will they be stored? Let's start with the basics: deciding what type of user personalization you need for your virtual desktop infrastructure (VDI) deployment.
Debating unique vs. mandatory user profile
If your users are all identical, faceless drones who do the same tasks every day, then you can safely deploy VDI with mandatory user profiles. Rather than unique user profiles, these are great for a consistent environment tailored to getting a limited set of tasks done. A mandatory user profile allows for greater consistency; every user gets the same settings every time they log on, and any changes they make are discarded at logoff.
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This type of profile is best suited to environments that want to deliver what users need at a minimal cost -- a call center with low margins and high staff turnover, for example. That way, IT doesn't have to make a lot of changes when employees leave, and there's less maintenance and updating.
For IT admins who are providing desktops to thinking and breathing unique individuals, things are a little more complicated. One of the reasons that PCs became popular with users is that the P stands for "personal." PC users expect their computing environment to be about them, remember settings choices and reflect their preferences.
Reaching that level of user personalization is an important step to getting your users to embrace VDI in the first place. VDI only succeeds if users are happy accessing a virtual desktop, and the user experience is paramount.
Copying and storing user profiles
Windows roaming profiles. The conventional way to store user uniqueness is with Windows roaming profiles, which brings some painful memories to us old-timers. The good news is that with VDI, you usually have better storage for roaming profiles, a faster network connection to the profile share, and users usually only log on to one desktop at a time.
Some challenges remain, particularly the time it takes to copy the profile from the share at logon and then copy it back at logoff. Remember, the VDI user profile can be thousands of little files that need to be copied to the virtual desktop's system disk while the user waits. Make sure your VDI storage can cope with this, especially if a lot of users log on at the same time (such as the beginning of the office day).
Using folder redirection to minimize the size of the roaming profile is also critical to reducing the logon and logoff time. The files in redirected folders are not copied at logon; they remain on a network share and are accessed from the share. Every file in a redirected folder is one less disk transaction at logon. Redirected folders also have benefits for the small population of users that use both a virtual desktop and another desktop; the redirected folders can be shared while the roaming profile generally cannot.
Using an agent. Other user profile management tools use an agent on the desktop and some kind of store, file share or database. These tools almost always go beyond what roaming profiles offer.
Some allow user-installed applications in nondedicated virtual desktops or migration between operating systems. That capability is helpful for complex VDI deployments or shops that want to migrate from Windows XP to Windows 7. There are a range of options, so make sure you consider whether the solution you choose affects supportability for a critical application or even the OS. Microsoft stands behind its own roaming profiles, but it is less likely to help with other issues.
Restoring damaged user profiles
The user's profile is valuable, so you need to work out how to restore it if the user or an application makes a mess. That means you need to back up VDI user profiles. Roaming profiles have been around for a while, so most decent backup software have long since worked with profile shares.
Of course, the content of the profile share is only as current as the last successful logoff by the user. This means that mandatory daily logoff is a good policy to enable up-to-date backups. Making daily logoff part of your virtual desktop policy makes this far easier; you can use the session timeout and logoff settings for the desktops to enforce daily logoff.
If you are not holding user uniqueness in profile shares, then think carefully about how you will restore a damaged profile. VMware's persistent disk is one possible store, but it's very hard to back up and restore, so it's better suited to just caching user profiles than serving as the sole repository. This caching effect is also useful to reduce the logon time, because the copy in the persistent disk will probably be up to date and not require copying.
If you choose a user profile management tool that stores profiles to a database, make sure it has built-in versioning. The last thing you want is to have to restore a whole database and roll back every profile to restore one user's profile.
Users are unique, and they want their desktop to be a reflection of that uniqueness. Allowing and protecting this uniqueness is a critical part of ensuring the acceptance of a VDI project. It can also be one of the bigger challenges.