Q: Why is the ``high water mark'' in my /etc/swaptab ignored?

A: This is probably due to an extra space in /etc/swaptab. The format of this file must be exactly as in swaptab(5), without spaces after the commas. Thus

#
# /etc/swaptab
#
/private/vm/swapfile lowat=20971520,hiwat=73400320  # 20/70 MB

works as expected, but in

#
# /etc/swaptab
#
/private/vm/swapfile lowat=20971520, hiwat=73400320  # 20/70 MB

the hiwat is  ignored (note the space after the first comma).

Valid for 1.0, 2.0, 3.0, 3.1

QA881