March 5, 2012 at 11:13 am
Page life expectancy drops frequently with a value less than 300 secs. Does it mean that memory needs to be increased?
Thanks
March 5, 2012 at 2:31 pm
It depends. The 300 number is not a hard threshold and in my experience, on most systems you'll be well above that the majority of the time. Some things that I'd look at:
What is the normal value for this?
What is happening at the time the it drops to its lowest level?
What's your buffer cache hit ratio? Is it dropping as well?
Are you seeing an increase in disk activity at this time as well?
Jack Corbett
Consultant - Straight Path Solutions
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March 5, 2012 at 2:47 pm
It depends. The 300 number is not a hard threshold and in my experience, on most systems you'll be well above that the majority of the time. Some things that I'd look at:
What is the normal value for this?
for every one hour below is the values for PLE
115
174
257
205
148
103
202
131
What is happening at the time the it drops to its lowest level?
Peak time....
What's your buffer cache hit ratio? Is it dropping as well?
Buffer cache hit ration is above 99%
Are you seeing an increase in disk activity at this time as well?
No disk activity...
March 5, 2012 at 2:53 pm
It looks like you are experiencing memory pressure as you are consistently seeing low PLE values. You should read, http://qa.sqlservercentral.com/articles/Memory/74867/ as it gives a decent outline of how to check memory issues.
Jack Corbett
Consultant - Straight Path Solutions
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March 6, 2012 at 7:55 am
Actually server is 2005 32 bit enterprise and Windows server is 2003 SP2 enterprise(my understanding is 32 bit enterprise will take max memory of OS without need to enable AWE?).
Memory is assigned to use is 4GB and Host memory is 16GB. Can i increase the SQL memory to 6GB to resolve the PLE issue?
March 6, 2012 at 8:18 am
Admingod (3/6/2012)
(my understanding is 32 bit enterprise will take max memory of OS without need to enable AWE?).
Without AWE enabled 32 bit SQL (regardless of edition) can use no more than 1.7GB of memory.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
March 6, 2012 at 8:31 am
So i need to enable AWE to user more than 1.7GB?
March 6, 2012 at 8:32 am
Yes, that or upgrade to 64-bit SQL
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability
March 7, 2012 at 2:16 pm
Admingod (3/6/2012)
Actually server is 2005 32 bit enterprise and Windows server is 2003 SP2 enterprise(my understanding is 32 bit enterprise will take max memory of OS without need to enable AWE?).Memory is assigned to use is 4GB and Host memory is 16GB. Can i increase the SQL memory to 6GB to resolve the PLE issue?
What is there in boot.ini file ? Paste the complete contents.
Is /PAE switch present there ?
We had the same problem on win 2003 enterprise 32bit where the PTE's where constantly dropping and the server was completely halted.
Refer to below links for a good explanation of how /PAE works:
http://technet.microsoft.com/en-us/library/cc736309(WS.10).aspx
http://blogs.technet.com/b/clint_huffman/archive/2008/04/07/free-system-page-table-entries-ptes.aspx
______________________________________________________________________________________________________________________________________________________________________________________
HTH !
Kin
MCTS : 2005, 2008
Active SQL Server Community Contributor 🙂
March 7, 2012 at 2:16 pm
Admingod (3/6/2012)
Actually server is 2005 32 bit enterprise and Windows server is 2003 SP2 enterprise(my understanding is 32 bit enterprise will take max memory of OS without need to enable AWE?).Memory is assigned to use is 4GB and Host memory is 16GB. Can i increase the SQL memory to 6GB to resolve the PLE issue?
What is there in boot.ini file ? Paste the complete contents.
Is /PAE switch present there ?
We had the same problem on win 2003 enterprise 32bit where the PTE's where constantly dropping and the server was completely halted.
Refer to below links for a good explanation of how /PAE works:
http://technet.microsoft.com/en-us/library/cc736309(WS.10).aspx
http://blogs.technet.com/b/clint_huffman/archive/2008/04/07/free-system-page-table-entries-ptes.aspx
______________________________________________________________________________________________________________________________________________________________________________________
HTH !
Kin
MCTS : 2005, 2008
Active SQL Server Community Contributor 🙂
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