Source. And a source for non-journalled quotas.

aptitude install quota

Edit fstab to make the proper entry look like this:

/dev/sda2       /               ext3    errors=remount-ro,usrjquota=aquota.user,,jqfmt=vfsv0 0       1

I don’t know if errors=remount-ro is a default option that will be enabled anyway. I would guess so.

Do this:

touch /aquota.user /
chmod 600 /aquota.*
mount -o remount /


quotacheck -avugm
quotaon -avug

WIth this command, you can set a 1GB quota for a user:

setquota -u $user 0 1000000 0 0  /

Other tools of interest: edquota, repquota. See the seealso for any quata command, I guess.