HP ML570 Novell NetWare 6 performance tuning guidelines for ProLiant servers - Page 8

Novell NetWare 6 performance tuning guidelines for ProLiant servers For example, the theoretical maximum achievable throughput on a 66 MHz PCI when a 32-bit bus master bursting with a 32-bit target would be: 4 bytes per data phase x 66 million data phases per second = 264 MB / second monitoring the disk subsystem in NetWare 6 Utility tools such as Monitor, NetWare Remote Manager (NRM), and SET parameters can be used to gauge disk subsystem performance in NetWare 6. These utilities provide clues as to whether there is a performance bottleneck in the disk subsystem. The following are parameters to monitor: • dirty cache buffers - Number of cache buffers containing updated data that has not been written to the disk. The operating system writes the data to the disk either as soon as the cache buffer is filled or when the dirty cache delay time elapses (default 3.3 seconds). • current disk requests - Number of pending disk I/O requests that are queued for service. • least recently used (LRU) settings - 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 LRU buffer. • Novell Storage Services (NSS) cache buffers - Check the cache buffers used by the NSS. To view the statistics shown in table 4, type the following at the console prompt: NSS / Cachestats table 4. buffer cache statistics statistics cache num cache buffer 512 num hash buckets 524288 min OS free cache buffers 256 num cache pages allocated 233106 cache hit percentage 76 cache hit 69803 cache miss 21624 percent of buckets used 0% max entries in a bucket 1 total entries 1286 Check the values for the Cache hit percentage and the Percent of buckets used on the displayed result. • Cache hit percentage provides a percentage of how the cache is performing. A percentage value of > 75 is desirable. • Percent of buckets used provides a percentage of the total cache currently in use. 8