Managing Xymon Server Data Disk Usage

I've been watching disk usage grow on a Xymon server for about the past
six months, and this growth seems fairly steady and linear.

The big directories are histlogs and hostdata.

After digging into the documentation, I'm wondering what strategies
Xymon admins prefer for managing disk usage.

I've read through man pages for TRIMHISTORY and XYMOND_HISTORY, with its
options.