Posted by mikeb on December 31, 2008
What are “Page Faults” you might ask.
Well if you were to plug into Google(r) you would find many definitions. All will fall along the same lines.
“An interrupt that occurs when a program requests data that is not currently in real memory. The interrupt triggers the operating system to fetch the data from a virtual memory and load it into RAM.
An invalid page fault or page fault error occurs when the operating system cannot find the data in virtual memory. This usually happens when the virtual memory area, or the table that maps virtual addresses to real addresses, becomes corrupt.” as defined by Webopedia – Internet.com
Or you could go with PC Mag’s version:
“A virtual memory interrupt that signals that the next instruction or item of data is not in physical memory and must be swapped back in from the disk. If the required page on disk cannot be found, then a page fault error occurs, which means that either the operating system or an application has corrupted the virtual memory. If such an error occurs, the user has to reload the application.”
Now to my evening/morning …
“Mike, it appears we have a network problem …”
“Okay, have you verified the settings?” I ask, wondering to myself if OSI now stands for ‘O, see, I… uhh…’
“No.” is the expected and returned response.
“Well, okay. I can go to the client and check settings and run some tests.” already knowing this is going to be a late night, “When will the client be ready for me to take the network down for testing?”
At this point many join in the fray offering up times. I interject that it sounds like 2200CST is a good start time.
We all agreed.
What, low and behold, to my wondering eyes did appear but … millions and millions of tiny page faults increasing by hundreds of thousands did appear! (sorry too close to Christmas, though just recently past.)
Once this process and application were closed everything worked as expected. But what should I hear but many tiny voices, developer’s my dear, cry in agony “No way! It can’t be us this year!”
Okay okay I have to stop. lol simply put, if you see massive unexplainable page faults and you have dutifully followed basic troubleshooting skills (using the OSI model as reference of course) then perhaps you might have an application issue.
I decided we were done. Completed what was needed for today, the client is happy, and the team can all be sent home.
Good night one and all and Happy New Year!
… but does it matter?