Historical data not available

I've noticed that a lot of times when I try to click on one of the
historical status pages in Xymon, I get a message that says
"Historical status log not available". This even happens for very
recent historical pages.

Then I looked at the history.log file and saw a whole bunch of these messages:

          2012-03-16 12:06:31 Historylog directory
/export/home/hobbit/data/histlogs has less than 5% free space -
disabling save of data for 5 minutes


But /export/home/hobbit/data/histlogs has plenty of free space left:

          (hobbit)@hobbit:~$ df -h /export/home/hobbit/data
          Filesystem Size Used Avail Use% Mounted on
          /dev/md/dsk/d30 7.9G 4.0G 3.9G 51% /export/home


Anyone know what's going on?


Thanks,
Ray