TABLE 1: Key Performance Metrics to Monitor
Object	Counter	Reason to Monitor
PhysicalDisk and LogicalDisk	Disk Transfers/sec (all instances)	On average, a modern SCSI hard disk can support about 80 to 100 transfers/sec before its response time erodes past an acceptable limit.
	Avg. Disk sec/Transfer (all instances)	These counters measure the time required to complete a read or write transaction. Developing your performance baseline and comparing it with this value shows whether your disk subsystem is running faster or slower than usual.
	Avg. Disk Queue Length (all instances)	If these counters' values are greater than 2 on one drive, you might have a disk-bottleneck problem. For RAID arrays, if the LogicalDisk Avg. Disk Queue Length is greater than twice the number of disks in the array, you have a disk bottleneck.
Memory	Pages/sec	If this value is high (i.e., a high value for Pages/sec is relative to your system) for consistent periods of time (i.e., longer than 5 minutes) and the physical disk where your pagefile resides is experiencing a high workload, you have a memory bottleneck. On a lightly loaded server, a Pages/sec value of 20 is high. On a workstation, a value of 4 might be high. Baseline your environment, and watch closely for dramatic increase in this counter; increased disk activity on the disk that contains your pagefile, the pagefile usage size, and low available memory bytes.
	Available Bytes	This counter shows the amount of RAM still available. You want your system to use all its RAM, but if this counter consistently drops below 4MB, you need more RAM.
Paging File	% Usage (all instances)	These values are helpful in assessing whether you have a memory problem. If Pages/sec increases and the pagefile grows, your system is running low on memory.
Processor	% Processor Time	This counter tracks CPU usage. If this value is consistently greater than 90 percent and the system work queue is greater than 2 overtime, you have a CPU bottleneck.
System	Processor Queue Length	One queue exists for processor time even on systems with multiple CPUs. This counter measures the number of threads in the queue that are ready for execution. If this value is greater than 2 for a single-CPU system (or twice the number of CPUs in a multi-CPU system) and the processor usage is greater than 90 percent, you probably have a CPU bottleneck.
Network Interface	Bytes Total/sec	This counter lets you isolate performance-related network problems. If this value is greater than 50 percent of its network medium, a network bottleneck is forming.