martes, 20 de diciembre de 2016

Windows. Performance Counters. Memory

My top performances counters to messure Windows Memory 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

[ ] Available MBytes


Counter:
Memory - Available MBytes
Description
Available Bytes is the amount of physical memory, in bytes, immediately available for allocation to a process or for system use. It is equal to the sum of memory assigned to the standby (cached), free and zero page lists. Indicates how much memory is available for new processes.
Measures values that sit between Available Bytes and Available Mbytes. The level of detail provided by tracking kilobytes is better than the limited detail of megabytes and the overwhelming detail of bytes.
Threshold / Values
Good -> big value
Units
Bytes / Mbytes
How to interpret the value
High value a lot of memory free to work else Possible memory congestion by processes. Solution: more memory

[ ] Pages/sec


Counter:
Memory - Pages/sec
Description
Pages/sec is the rate at which pages are read from or written to disk to resolve hard page faults. This counter is a primary indicator of the kinds of faults that cause system-wide delays.  It is the sum of Memory\\Pages Input/sec and Memory\\Pages Output/sec.  It is counted in numbers of pages, so it can be compared to other counts of pages, such as Memory\\Page Faults/sec, without conversion. It includes pages retrieved to satisfy faults in the file system cache (usually requested by applications) non-cached mapped memory files.

This counter indicates how many times the virtual memory is getting accessed. A rule of thumb says that it should be lower than 20. Higher numbers might mean excessive paging. Using Memory: Page Faults/sec can further indicate whether SQL Server or some other process is causing it.

Is used to track the number of virtual memory pages read or written per second. On most systems, a 4KB memory page is used, so you can multiply the Pages/sec value times 4 to calculate the kilobytes passing to or from the virtual memory file each second, which will give you a better understanding of just how much data is moved from RAM to the disk each second.

Threshold / Values
Good < 20
Units
Pages/sec
How to interpret the value
Access to disk (cache). Higher numbers might mean excessive paging.



[ ] Pages Output/sec


Counter:
Memory - Pages Output/sec
Description
Pages Output/sec is the rate at which pages are written to disk to free up space in physical memory. Pages are written back to disk only if they are changed in physical memory, so they are likely to hold data, not code. A high rate of pages output might indicate a memory shortage. Windows writes more pages back to disk to free up space when physical memory is in short supply.  This counter shows the number of pages, and can be compared to other counts of pages, without conversion.
Threshold / Values
Good low values
Units
Pages Output/sec
How to interpret the value
A high rate of pages output might indicate a memory shortage. Need more physical memory.

[ ] Pages Input/sec


Counter:
Memory - Pages Input/sec
Description
Pages Input/sec is the rate at which pages are read from disk to resolve hard page faults. Hard page faults occur when a process refers to a page in virtual memory that is not in its working set or elsewhere in physical memory, and must be retrieved from disk. When a page is faulted, the system tries to read multiple contiguous pages into memory to maximize the benefit of the read operation. Compare the value of Memory\\Pages Input/sec to the value of  Memory\\Page Reads/sec to determine the average number of pages read into memory during each read operation.
Threshold / Values
Good high values
Units
Pages Input/sec
How to interpret the value
Hard page faults occur when a process refers to a page in virtual memory that is not in its working set or elsewhere in physical memory, and must be retrieved from disk.






by GoN | Published: December 15, 2016 | Last Updated: - 

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