Referring back to this question:
Have a use case where the monitoring tools are pretty basic, and we can't add SNMP to the server. We keep getting warnings that the memory usage is out of hand - however, it is merely the disk cache. I want to still set a monitoring alert on the server for a real problem, but short of setting it to 99%, I'd like to limit the memory usage of the disk cache to around 90% so that if it does go over that than we can get a 'real' alert, if you follow.
It seems as though Chris' answer (on previous Q) might be the best though.
Any other suggestions on how this may be achieved?