Windows. Performance Counters. LogicalDisk

My top performances counters to messure Windows Logical Disk performance.

These are some of the explanations that I have been able to extract from Microsoft and other web pages. The interpretations of the counters could vary according to parameters or configurations that each one can have.

[ ] Performance Counters

[ ] LogicalDisk

[ ] Avg. Disk sec/Read

Counter:	LogicalDisk - Avg. Disk sec/Read
Description	Avg. Disk sec/Read is the average time, in seconds, of a read of data from the disk. Measure latency directly at the layer just above where the storage device drivers hook into the operating system. These help to accurately measure how long the drivers and hardware took to service an I/O request no matter what kind of hardware you have.
Options	Total or Disk values
Threshold / Values	Measures read latency on the disks. ( < .005 excellent; .005 – .010 Good; .010 – .015 Fair; > .015 investigate)
Units	seconds
How to interpret the value

  

[ ] Avg. Disk sec/Write

Counter:	LogicalDisk - Avg. Disk sec/Write
Description	Avg. Disk sec/Write is the average time, in seconds, of a write of data to the disk. Measure latency directly at the layer just above where the storage device drivers hook into the operating system. These help to accurately measure how long the drivers and hardware took to service an I/O request no matter what kind of hardware you have.
Options	Total or Disk values
Threshold / Values	Measures write latency on the disks. ( < .005 excellent; .005 – .010 Good; .010 – .015 Fair; > .015 investigate)
Units	seconds
How to interpret the value

[ ] Disk Read/sec

Counter:	LogicalDisk - Disk Read/sec
Description	Disk Reads/sec is the rate of read operations on the disk. Number of read IOPs.
Options	Total or Disk values
Threshold / Values
Units	seconds
How to interpret the value

[ ] Disk Write/sec

Counter:	LogicalDisk - Disk Write/sec
Description	Disk Writes/sec is the rate of write operations on the disk. Number of write IOPs.
Options	Total or Disk values
Threshold / Values
Units	seconds
How to interpret the value

[ ] Average Disk Queue Length

Counter:	LogicalDisk - Average Disk Queue Length
Description	Avg. Disk Queue Length is the average number of both read and write requests that were queued for the selected disk during the sample interval. Avg. Disk Queue Length (Avg. Disks Read Queue Length, Avg. Disk Write Queue Length) Avg. Disk Queue Length is equal to the (Disk Transfers/sec) *( Disk sec/Transfer) , which is the average response of the device times the I/O rate. As you would expect, the Avg. Disk Read Queue Length is equal to the “(Disk Reads/sec) * (Disk sec/Read)” and Avg. Disk Write Queue Length is equal to the “(Disk Writes/sec) * (Disk sec/Write)”. Counter can reveal whether the drive is keeping up with the demand of running processes. The most frequently cited threshold is two items in the queue. If the average is greater than 2, a drive bottleneck might be occurring. This counter should also be compared with the baseline. If the baseline shows an average of 2.3 items in the disk queue and performance was perceived as acceptable, there’s no reason to suggest that performance is unacceptable—at a later time—if the average is the same or lower. Remember, performance is measurable with statistics, but whether performance is “good” or “bad” is a relative issue. The Avg. Disk Queue Length counter is derived from the product of Avg. Disk sec/Transfer multiplied by Disk Transfers/sec. For example, the Avg. Disk Queue Length counter reads 10.3, and the Current Disk Queue Length counter shows four requests in the disk queue at the end of the measurement interval. If the previous value of Current Disk Queue Length was 0, the equilibrium assumption necessary for Little's Law does not hold. Since the number of arrivals is evidently greater than the number of completions during the interval, there is no valid interpretation for the value in the Avg. Disk Queue Length counter, and you should ignore the counter value. However, if both the present measurement of the Current Disk Queue Length counter and the previous value are equal, then it is safe to interpret the Avg. Disk Queue Length counter as the average number of outstanding I/O requests to the disk over the interval, including both requests currently in service and requests queued for service.
Options	Total or Disk values
Threshold / Values	1 < Good /  3<=Fair (base on  baseline)
Units
How to interpret the value	Counter can reveal whether the drive is keeping up with the demand of running processes. The most frequently cited threshold is two items in the queue. If the average is greater than 2, a drive bottleneck might be occurring. This counter should also be compared with the baseline. If the baseline shows an average of 2.3 items in the disk queue and performance was perceived as acceptable, there’s no reason to suggest that performance is unacceptable—at a later time—if the average is the same or lower. Remember, performance is measurable with statistics, but whether performance is “good” or “bad” is a relative issue. Be careful when using old thresholds of 2 with SQL Server and SANs.  This value can be much higher than 2.  Do not rely solely on this counter to diagnose an IO problem. Possible HD problems.

[ ] Disk Bytes/sec

Counter:	LogicalDisk - Disk Bytes/sec
Description	Disk Bytes/sec is the rate bytes are transferred to or from the disk during write or read operations. Perfmon captures the total number of bytes sent to the disk (write) and retrieved from the disk (read) over a period of one second. If the Perfmon capture interval is set for anything greater than one second, the average of the values captured is presented. The Disk Read Bytes/sec and the Disk Write Bytes/sec counters break down the results displaying only read bytes or only write bytes, respectively.
Options	Total or Disk values
Threshold / Values	Good < 1. High values are Good if this value is low could have problems.
Units	Seconds
How to interpret the value	Can reveal whether the drive is living up to expectations. Many drives are rated at a certain speed, but they perform at lower speeds. This counter can reveal such behavior. In many cases, updating drive controller drivers might resolve such performance problems.

[ ] Disk Transfers/sec

Counter:	LogicalDisk - Disk Transfers/sec
Description	Disk Transfers/sec is the rate of read and write operations on the disk. Perfmon captures the total number of individual disk IO requests completed over a period of one second. If the Perfmon capture interval is set for anything greater than one second, the average of the values captured is presented. Disk Reads/sec and Disk Writes/sec are calculated in the same way, but break down the results in read requests only or write requests only, respectively.
Options	Total or Disk values
Threshold / Values	Good < 1. High values are Good if this value is low could have problems.
Units	Seconds
How to interpret the value	Number of read and write IOPs (used to compare against capacity of storage subsystem)

[ ] Split IO/Sec

Counter:	LogicalDisk - Split IO/Sec
Description	Split IO/Sec reports the rate at which I/Os to the disk were split into multiple I/Os. A split I/O may result from requesting data of a size that is too large to fit into a single I/O or that the disk is fragmented. Measures the rate of IO split due to file fragmentation. This happens if the IO request touches data on non-contiguous file segments.
Options	Total or Disk values
Threshold / Values	High values are Bad, there are a lot of fragmentation.
Units
How to interpret the value	Measures the rate of IO split due to file fragmentation. This happens if the IO request touches data on non-contiguous file segments.

[ ] Tools

https://gallery.technet.microsoft.com/DiskSpd-a-robust-storage-6cd2f223

[ ] More Information

https://www.smartertools.com/blog/2016/07/15-configure-perfmon-to-prevent-disk-issues

by GoN | Published: December 17, 2016 | Last Updated: Febrary 16, 2017