How can I increase the time before my external drive powers down?

I have an external USB drive from LaCie that is connected to my MacBook Pro – almost all the time. So whenever I don't use it for a few minutes, it powers down. That means, it takes a few seconds to spin the disk up again if I need it.

Sometimes, other applications wake the drive up even when I don't want to, causing the applications to hang (i.e. wait for the drive).

How can I increase the time before the external drive powers down?

Cocktail is an award winning general purpose utility for Mac OS X

This app does exactly what you are after (plus much much more), but it will set you back $15.

Alternatively, the command pmset appears to do this as well, but without the fancy GUI. For example pmset -c disksleep 60 will prevent all disks from spinning down within 60 minutes of activity when plugged in. You can change the -c part to specify a different power condition:

The -a, -b, -c, -u flags determine whether the settings apply to battery ( -b ), charger (wall power) ( -c ), UPS ( -u ) or all ( -a )

Keep Drive Spinning is a free alternative that does what you want.

The externals sleep routine is set by the drive's firmware. A few can respond to Energy Saver/Cocktail/pmset settings, most cannot. The only way to keep a drive is to have an app/script write to it at intervals. The video editing folks need this and their forums are where to look for answers.