Hi, I would like to inquiry how the PI system will be affect if the paging file usage is low or high??
Not PI System specific: High page file usage means the system does not have enough physical RAM to store everything the system wants to put into memory. This is not always an immediate problem, though it is certainly a sign that your system could benefit from more RAM. Infrequently accessed memory items can probably safely live in the page file (programs that are idle, for example, can safely have their items swapped to the page file). To determine whether or not this is immediately impacting the performance of your system you must dig deeper. Try looking at Memory\Pages per Second, which tells you how often the system is reading from the disk to fill memory request. You should also monitor your disk performance (on the *physical* drive that stores the page file): disk queues, IO rates, % active time. I would recommend reading Use PerfMon to Diagnose Common Server Performance Problems .
PI System: Your PI system uses a lot of RAM when your archives and databases are large. You should have enough RAM on your system to put your 3 most recent archives into RAM. The Data Archive is, of course, a database, so overall performance is highly dependent on disk performance. It must write new incoming values into the archives, and also read archives and snapshot for all incoming user requests.
If your system does not have enough RAM you will lower performance by forcing increased reads from disk to service user requests. The next phase of performance degradation will occur if your page file is on the same *physical* disk as your archives, in which case the archive and the page file will be competing. All archiving and requests will need to slow down and line up to be serviced by the overworked disk.
Thank you for the explanation and info.
Do have any more questions? If not, can you click the "Correct Answer" button?
Yes. I still have a question about the page index.
Normally we can see the write page index and read page index(piartool -qs) should be the same value. What if the result show different value for both index??
Do you know in what circumstances will the value be different??
Hi Lim. This sounds like a totally different problem to me? If so, perhaps we should address in a new thread?
However, Output from piartool -qs says
"Under normal conditions, these two numbers are identical. If PI Archive Subsystem is not reading at the same pace that PI Snapshot Subsystem is writing, page shifts will occur and the Total Page Shifts counter will increment." This means that if there are enough events in the queue to fill a couple of pages. Either way, don't hesitate to post the output.
(Still, if this is not related to your hardware monitoring questions, best to create another thread.)
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