Sizing the SBS OS Partition
How big a partition should you use for the operating system on a Windows Small Business Server? Normally I wouldn't find this subject worth blogging about, but it's started to get my attention that this is a problematic area.

Because Dell and other vendors are shipping many of their servers with mirrored OS drives preconfigured at 16gb, many technologists are making it a point of pride to make that sufficient, when in fact, it isn't. Someone will ask in the newsgroups what size partitions they should use for the OS, and many otherwise highly proficient net admins are recommending that 16gb or even 10gb should be enough, "when managed well." Poppycock.

By saying this, they imply that if you can't keep your OS problem-free on a small partition, you simply aren't as good a server admin. That's like a person saying that careful drivers need never carry a spare tire, since a driver who is a good driver won't be running over things likely to puncture a tire, and then going on to give prospective drivers advice about how to avoid flats. There may be some truth to it, since, for example, I consider myself a good driver and have never had a flat in 20 years of driving, but it's still a bad recommendation.

In my experience, it's safer to go with at least a 40gb OS partition. Might that be a waste of the space I never end up using on that partition? Since when is the goal to fill up a drive? Sometimes there are things that happen out of ones control that makes it worth the possibility of "wasting" up to 20gb.

For example, one of my clients is a 20-user engineering firm. The technical lead there decided to install Axium's accounting software on the server. He left the default paths, and it was installed on C:. It was a complex install and he spent several hours working with their support to get it all working. A few weeks later it comes up on my radar when I begin to get disk space alerts. Sure, they should have asked before installing, but it wouldn't have been as big an issue if I'd had more than a Dell-default 16gb OS partition.

There are other sources of temporary ballooning. It's easy to end up with Symantec AV and its definitions on C if you aren't on the ball during the install, etc.

In any case, it's more often helpful to have a larger partition just to keep the free-space ratio high to handle file fragmentation more efficiently and keep ample room available for ShadowCopy's use.

My basic question to system configurers: why set yourself up for a failure? Give yourself some space to accommodate whatever less-than ideal install situations may get forced on you. Especially since 20gb costs less than a billable hour. Choosing to work with 16gb or less is a decision to make the likelihood of additional billable time more likely.

Making a larger OS partition is a customer-centric decision, and in my mind choosing a smaller partition is on the same motivational continuum as choosing to overclock a server. "Because you can."  ¶ 5:52 PM