Novell NETWARE 6-DOCUMENTATION Manual page 2934

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Server Memory Administration Guide
time stamp of the last block in the cache list. (The time stamp is the time at
which the last block entered the list.) The result is displayed in HH:MM:SS.0
format. The LRU Sitting Time measures the length of time it takes for a cache
buffer at the head of the list to make its way down to the tail, where it becomes
the least recently used (LRU) buffer. Every cache buffer in the list is being
reused within that period of time.
In configurations with excessive cache, the LRU Sitting Time can be very
high, even many hours. In configurations with too little cache, the LRU Sitting
Time can be measured in seconds. The time can vary widely, depending on
circumstances.
On inactive servers, such as those sitting unused overnight or those in lab
environments with long periods of idle time, the LRU Sitting Time statistic is
incremented by one second every second. This is because the LRU Sitting
Time indicates the age of the LRU cache buffer. The LRU Sitting Time
statistic is useless under these circumstances, except to confirm the obvious:
that new data is not being written to the server's cache. This statistic is most
useful during peak workloads when the server's cache is servicing the greatest
number of users and the broadest possible data set.
You can view the LRU Sitting Time statistic using NetWare Remote Manager
or MONITOR.
In NetWare Remote Manager, do the following:
1
Click the View Memory Config link in the navigation frame.
2
Click the Traditional File System Cache Statistics link on the System
Memory Information page.
In MONITOR, from the Available Options menu, select Disk Cache
Utilization.
Calculating Cache Memory Needs
To determine how much file cache your server needs, do the following:
1
Track server resource utilization statistics. Chart the results for daily,
weekly, monthly, period-end, and year-end cycles. Identify recurring
periods of peak workloads.
2
Observe the LRU Sitting Time statistic during peak workload periods of
the day. Keep a record of the lowest LRU Sitting Time during the peak
periods for at least one week, longer if necessary, to see a consistent
pattern.