LogicalDisk Object

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

The LogicalDisk performance object consists of counters that monitor logical partitions of hard or fixed disk drives. System Monitor identifies logical disks by their drive letter, such as "C."

Counter Name Description Counter Type

% Disk Time

Shows the percentage of time that the selected disk drive was busy servicing read or write requests.

PERF_PRECISION_100NS_TIMER

% Disk Read Time

Shows the percentage of time that the selected disk drive was busy servicing read requests.

PERF_PRECISION_100NS_TIMER

% Disk Write Time

Shows the percentage of time that the selected disk drive was busy servicing write requests.

PERF_PRECISION_100NS_TIMER

% Free Space

Shows the percentage of the total usable space on the selected logical disk drive that was free.

PERF_RAW_FRACTION

Avg. Disk Bytes/Read

Shows the average number of bytes transferred from the disk during read operations.

PERF_AVERAGE_BULK

Avg. Disk Bytes/Transfer

Shows the average number of bytes transferred to or from the disk during write or read operations.

PERF_AVERAGE_BULK

Avg. Disk Bytes/Write

Shows the average number of bytes transferred to the disk during write operations.

PERF_AVERAGE_BULK

Avg. Disk Queue Length

Shows the average number of both read and write requests that were queued for the selected disk during the sample interval.

PERF_COUNTER_LARGE_QUEUELEN_TYPE

Avg. Disk Read Queue Length

Shows the average number of read requests that were queued for the selected disk during the sample interval.

PERF_COUNTER_LARGE_QUEUELEN_TYPE

Avg. Disk sec/Read

Shows the average time, in seconds, of a read operation from the disk.

PERF_AVERAGE_TIMER

Avg. Disk sec/Transfer

Shows the time, in seconds, of the average disk transfer.

PERF_AVERAGE_TIMER

Avg. Disk sec/Write

Shows the average time, in seconds, of a write operation to the disk.

PERF_AVERAGE_TIMER

Avg. Disk Write Queue Length

Shows the average number of write requests that were queued for the selected disk during the sample interval.

PERF_COUNTER_LARGE_QUEUELEN_TYPE

Current Disk Queue Length

Shows the number of requests outstanding on the disk at the time that the performance data is collected. It also includes requests in service at the time of the collection. This is a snapshot, not an average over a time interval. Multispindle disk devices can have multiple requests that are active at one time, but other concurrent requests are awaiting service. This counter might reflect a transitory high or low queue length, but if there is a sustained load on the disk drive, it is likely that this will be consistently high. Requests experience delays that are proportional to the length of this queue, minus the number of spindles on the disks. For good performance, this difference should average less than two.

PERF_COUNTER_RAWCOUNT

Disk Bytes/sec

Shows the rate, in incidents per second, at which bytes were transferred to or from the disk during write or read operations.

PERF_COUNTER_BULK_COUNT

Disk Read Bytes/sec

Shows the rate, in incidents per second, at which bytes were transferred from the disk during read operations.

PERF_COUNTER_BULK_COUNT

Disk Reads/sec

Shows the rate, in incidents per second, at which read operations were performed on the disk.

PERF_COUNTER_COUNTER

Disk Transfers/sec

Shows the rate, in incidents per second, at which read and write operations were performed on the disk.

PERF_COUNTER_COUNTER

Disk Write Bytes/sec

Shows the rate, in incidents per second, at which bytes were transferred to the disk during write operations.

PERF_COUNTER_BULK_COUNT

Disk Writes/sec

Shows the rate, in incidents per second, at which write operations were performed on the disk.

PERF_COUNTER_COUNTER

Free Megabytes

Shows the unallocated space, in megabytes, on the disk drive. One megabyte is equal to 1,048,576 bytes.

PERF_COUNTER_RAWCOUNT

See Also

Concepts

Finding Cache Bottlenecks
Find disk bottlenecks