Performance Counters & preferred Values

Performance Counter

Object	Counter	Preferred Value	Description
Memory	Available Mbytes	> 20MB
Memory	Free System Page Table Entries	> 7000	Free System Page Table Entries is the number of page table entries not currently in use by the system. If < 7000, consider removing /3GB.
Memory	Pages/Sec	< 50	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.
Memory	Pages Input/Sec	< 10	Pages Input/sec is the rate at which pages are read from disk to resolve hard page faults.
Paging File	%Usage	< 70%	The amount of the Page File instance in use in percent.
Paging File	%Usage	< 70%	The peak usage of the Page File instance in percent.
SQL Server: Buffer Manager	Page Life Expectancy	> 300	This performance monitor counter tells you, on average, how long data pages are staying in the buffer. If this value gets below 300 seconds, this is a potential indication that your SQL Server could use more memory in order to boost performance.
SQL Server: Buffer Manager	Lazy Writes/Sec	< 20	This counter tracks how many times a second that the Lazy Writer process is moving dirty pages from the buffer to disk in order to free up buffer space. Generally speaking, this should not be a high value, say more than 20 per second or so. Ideally, it should be close to zero. If it is zero, this indicates that your SQL Server's buffer cache is plenty big and SQL Server doesn't have to free up dirty pages, instead waiting for this to occur during regular checkpoints. If this value is high, then a need for more memory is indicated.
SQL Server: Buffer Manager	Checkpoint Pages/Sec	This value is relative, it varies from server to server, we need to compare the average to a base line capture to tell if the value is high or low.	When a checkpoint occurs, all dirty pages are written to disk. This is a normal procedure and will cause this counter to rise during the checkpoint process. What you don't want to see is a high value for this counter over time. This can indicate that the checkpoint process is running more often than it should, which can use up valuable server resources. If this has a high figure (and this will vary from server to server), consider adding more RAM to reduce how often the checkpoint occurs, or consider increasing the "recovery interval" SQL Server configuration setting.
SQL Server: Buffer Manager	Page reads/sec	< 90	Number of physical database page reads issued. 80 – 90 per second is normal, anything that is above indicates indexing or memory constraint.
SQL Server: Buffer Manager	Page writes/sec	< 90	Number of physical database page writes issued. 80 – 90 per second is normal, anything more we need to check the lazy writer/sec and checkpoint counters, if these counters are also relatively high then, it's memory constraint.
SQL Server: Buffer Manager	Free pages	> 640	Total number of pages on all free lists.
SQL Server: Buffer Manager	Stolen pages	Varies. Compare with baseline	Number of pages used for miscellaneous server purposes (including procedure cache).
SQL Server: Buffer Manager	Buffer Cache hit ratio	> 90%	- Percentage of pages that were found in the buffer pool without having to incur a read from disk.
SQL Server: Buffer Manager	Target Server Memory(KB)		Total amount of dynamic memory the server can consume.
SQL Server: Buffer Manager	Total Server Memory(KB)		Total amount of dynamic memory (in kilobytes) that the server is using currently
PhysicalDisk	Avg. Disk Sec/Read	< 8ms	Measure of disk latgency. Avg. Disk sec/Read is the average time, in seconds, of a read of data from the disk.
PhysicalDisk	Avg. Disk sec/Write	< 8ms (non cached) < 1ms (cached)	Measure of disk latency. Avg. Disk sec/Write is the average time, in seconds, of a write of data to the disk.
PhysicalDisk	Avg. Disk Read Queue Length	< 2 * spindles	Avg. Disk Read Queue Length is the average number of read requests that were queued for the selected disk during the sample interval.
PhysicalDisk	Avg. Disk Write Queue Length	< 2 * spindles	- Avg. Disk Write Queue Length is the average number of write requests that were queued for the selected disk during the sample interval.
SQL Server: Buffer Manager	Page reads/sec	< 90	- Number of physical database page reads issued. 80 – 90 per second is normal, anything that is above indicates indexing or memory constraint.
SQL Server: Buffer Manager	Page writes/sec	< 90	Number of physical database page writes issued. 80 – 90 per second is normal, anything more we need to check the lazy writer/sec and checkpoint counters, if these counters are also relatively high then, it's memory constraint.
SQL Server: Buffer Manager	Free pages	> 640	Total number of pages on all free lists.
SQL Server: Buffer Manager	Stolen pages	Varies. Compare with baseline	Number of pages used for miscellaneous server purposes (including procedure cache).
SQL Server: Buffer Manager	Buffer Cache hit ratio	> 90%	Percentage of pages that were found in the buffer pool without having to incur a read from disk.
Processor	%Processor Time	< 80%	% Processor Time is the percentage of elapsed time that the processor spends to execute a non-Idle thread.
Processor	%Privileged Time	< 30% of Total %Processor Time	% Privileged Time is the percentage of elapsed time that the process threads spent executing code in privileged mode.
Process (sqlservr)	%Processor Time	< 80%
Process (sqlservr)	%Privileged Time	< 30% of %Processor Time (sqlservr)	Note: Divide the value by number of processors
System	Context Switches/sec	< 3000	1500 – 3000 per processor Excellent – Fair > 6000 per processor Poor Upper limit is about 40,000 at 90 % CPU per CPU NOTE: Remember to divide by number of processors
System	Processor Queue Length	< 4 per CPU	For standard servers with long Quantums <= 4 per CPU Excellent < 8 per CPU Good < 12 per CPU Fair
SQLServer: Access Methods	Full Scans / sec	< 1	If we see high CPU then we need to invistigate this counter, otherwise if the full scan are on small tables we can ignore this counter. Values greater than 1 or 2 indicates that we are having table / Index page scans. We need to analyze how this can be avoided.
SQLServer: Access Methods	Worktables Created/Sec	< 20	Number of worktables created in tempdb per second. Worktables are used for queries that use various spools (table spool, index spool, etc).
SQLServer: Access Methods	Workfiles Created/Sec	< 20	Number of work files created per second. Tempdb workfiles are used in processing hash operations when the amount of data being processed is too big to fit into the available memory. They may be able to reduce this number by making the queries more efficient by adding/changing indexes, adding additional memory, etc.
SQLServer: Access Methods	Page Splits/sec	< 20	Interesting counter that can lead us to our table / index design. This value needs to be low as possible. If you find out that the number of page splits is high, consider increasing the fillfactor of your indexes. An increased fillfactor helps to reduce page splits because there is more room in data pages before it fills up and a page split has to occur.
SQLServer: General Statistics	User Connections		The number of users currently connected to the SQL Server.
SQLServer: General Statistics	Logins/sec	< 2	> 2 per second indicates that the application is not correctly using connection pooling.
SQLServer: General Statistics	Logouts/sec	< 2	> 2 per second indicates that the application is not correctly using connection pooling.
SQLServer: SQL Statistics	Batch Requests/Sec	< 1000	Over 1000 batch requests per second indicate a very busy SQL Server.
SQLServer: SQL Statistics	SQL Compilations/sec	< 10% of the number of Batch Requests / sec	The number of times per second that SQL Server compilations have occurred. This value needs to be as low as possible. If you see a high value such as over 100, then it's an indication that there are lots or adhoc queries that are running, might cause CPU.
SQLServer: SQL Statistics	SQL Re-Compilations/sec	< 10% of the number of SQL Compilations/sec	This needs to be nil in our system as much as possible. A recompile can cause deadlocks and compile locks that are not compatible with any locking type.
SQL Server: Latches	Average Latch Wait Time (ms)	< 300	Average latch wait time (milliseconds) for latch requests that had to wait.
SQL Server: Locks	Number of Deadlocks/sec	< 1	The number of lock requests that resulted in a deadlock.
SQL Server: Locks	Lock Requests/sec	< 1000	Number of requests for a type of lock per second. Lock requests/sec > 1000 indicates that the queries are accessing large number of rows, the next step is to review high read queries. If you also see high Avg. Wait time, then it's an indication of blocking, then review the blocking script output.
SQL Server: Locks	Average Wait Time (ms)	< 500	This is the average wait time in milliseconds to acquire a lock. Lower the value the better it is. If the value goes higher then 500, there may be blocking going on; we need to run blocker script to identify blocking.