Checks, Intervals and Loops Oh My - Part 3
By user12618589 on May 21, 2008
This is my final blog on the Number of Checks and Interval settings within Dirtracer.
Lets discuss one of the most basic elements of Dirtracer...the Main Performance Gathering Loop and two if its governing parameters.
NUMBEROFCHECKS and INTERVAL
NUMBEROFCHECKS # Number of checks: total number of loops
INTERVAL # Interval: seconds between loops
These two parameters tell Dirtracer how long to run and how many Main Loop data points to gather. The settings for these two parameters are totally dependent on the problem type you are gathering for.
The following are the data points normally gathered in the main loop; these are all of course configurable whether all, some or none are gathered all the time.
- netstat info
- ls -la from the transaction logs
- cn=monitor searches
- main cache searches; 1 search per loop.
- db cache searches; 1 search per backend per loop
As mentioned above an Admin can set the Number of Checks or "data points" to gather. Lets look at some example problem types versus the settings you may want to capture them with.
The Number of Checks and Interval parameters govern how many loops and how long the Main Loop runs for however they are also used when executing the following commands. These commands are launched before the Main Loop is engaged and will run in the background while the Main Loop is active.
See the man pages for iotstat, vmstat and mpstat for more information on these commands.
Please see my previous blog on pms.sh (Pmonitor) for more information regarding this script.