Long term cache hits

Besides the long term cache hits, you also need to take into account the LRU sitting time. This represents how long cache buffers in the LRU (Least Recently Used) queue were last referenced. If this number is less than an hour AND your long term cache hits are less than 80%, the indication is that you need more memory.
On the other hand, it could be that your Minimum Directory Cache Buffer parameter is set too low. Try increasing it from the Monitor, Server Parameters, Directory Caching Menu.
Hope this helps!

Another important resource for your problem is the Novell Support Connection Forums. I had a similar difficulty with my server and, adding ram did not fix the problem. The last reply was a good start.
Check the "Minimum Directory Cache Buffers" andMaximum Directory Cache Buffers" settings. If the minimum is set too low, you will run out- lowering your percentages. The best start is to set the minimum at or above the current amount: if you have 5000 allocated now, set the minimum to 5500. If the server allocates more, increase your minimum setting to that number or a bit more. Start by setting the maximum about 500 more than the minimum. This is the best fine tuning/optimization method to use. Over time, Netware is dynamically self tuninghowever, you need to record the settings and make them permanent parameters for reboots to get things optimized quickly. Too many directory searches using "dir" command will eat up cache buffers. Running large database queries will eat them up also.
Addidtionally, check the "Percent of Volume used by Directory" setting. I lowered mine to the minimum. My Long term cache hits fluctuate 94-95% and long term cache dirty hits remain constant at 99%; even with night ly database dumps they go only to92.
I increase my minimum cache buffers to whatever the peak is above the last setting.
Good luck