Q:

How to apply disk quota in ubuntu server on a VPS?

I have a VPS with ubuntu server 10.04 installed on it.Now I want to have some shell users with limited home folder size.
It seems quota is the best way to do this, but all tutorials require editing /etc/fstab and add usrquota or grpquota to /home partition options.
As my /etc/fstab looks like this:
proc  /proc       proc    defaults    0    0 
none  /dev/pts    devpts  rw          0    0

how can I apply quota?

A:

Your VPS provider may be doing tricks at boot-time resulting in your /etc/fstab not needing the root filesystem listed. You can find the device and other details from the output of the mount command. If you add those details to your /etc/fstab, you may be able to add the usrquota,grpquota options there for the next reboot.
If that doesn't work for your VPS, you may be able to approximate those mount options by turning them on later in the boot process. For example, I use usrjquota=aquota.user,jqfmt=vfsv0 on an ext3 filesystem. If I didn't have access to my /etc/fstab, I might try editing my /etc/rc.local and adding something like:
mount -o remount,usrjquota=aquota.user,jqfmt=vfsv0 /that/filesystem

