Windows Tip: Page files, system volumes, and large memory 64-bit systems

November 2, 2007 —

Send your Windows question to Mitch today! | See other Windows tips

Conventional wisdom is that your page file should be 1.5 times the size of
your system's RAM. The reasoning behind this is that in order to capture a Kernel
memory dump should Windows server crash, the page file size must be equal to
at least the amount of RAM on your system plus 128 MB. But since 64-bit Windows
servers often have huge amounts of memory, do you really need to allocate a
whopping 48 GB of hard drive space just to your page file on a system that has
32 GB of RAM? Some experts I know say No, since Windows Server 2003 offers you
the option of creating small memory dumps instead. Small memory dumps need only
2 MB of free disk space, so by configuring your server to create a small memory
dump instead of a full one, you can get away with having a much smaller system
volume on a large memory 64-bit system. But is this really a good idea? I doubt
it, since I know at least one company who got burned by doing this. What happened
was that when they built their servers they only made their system volumes big
enough to allow for small memory dumps. Then one day, for whatever reason, their
servers got so messed up that they had to bring in Microsoft Customer Support
Services (CSS) to help them remedy the situation. CSS tried analyzing the small
dumps but couldn't determine the problem, so they asked for Kernel dumps, and
to obtain these the admin at this company had to go through the painful process
of rebuilding the system volumes on all their servers to allow enough free space
for Kernel dumps to be captured.

The moral to me seems obvious ... don't skimp on sizing your system volume.
And if your system volume is also your boot volume then you need even more room
i.e. enough to contain the Windows operating system files, any service packs
and hotfixes you apply, all your installed applications, your page file, and
a Kernel dump file - plus some room to grow. All this can easily add up to 100
GB or more, and I'd personally recommend doubling that and using at least 200
GB for your boot/system volume. After all, just remember that old project management
rule of thumb: carefully figure out how much time, money and effort your project
will need, then double it. You don't want to leave your butt uncovered when
storage only less than a dollar per gigabyte nowadays.

ITworld