Can I set up quotas on my Time Capsule?
Whilst you can't restrict the size of Time Machine backups on a Time Capsule, you can reserve space for other files and Time Machine will expand to the remaining space.


Open Disk Utility and go to File → New → Blank Disk Image….
Give the image a file name, then select the options that you would like at the bottom of the window. Here you set the size that you want to reserve for other files.



The others should be set to default (but you can have a custom name).
Select your Time Capsule → Share as the destination for this image.
Click Create.


You can then store any files you wish inside this disk image and Time Machine will not intrude upon the space you selected when you created the image. You can change the size of the image later if you have sufficient space using the Resize button in Disk Utility.