> I have a query - Is there any wayout from which we would determine that > the linux machine had been idle for some time now, and in the meanwhile, > we could start some background process to do some housekeeping jobs - or > something of that sort..... Yes, this is very easy in Linux. There is a file on every Linux system named /proc/loadavg which contains the 1 minute, 5 minute, and 10 minute load averages for the system. The load is the number of processes that are waiting to run on the CPU, but which are blocked by a currently running process, and the X minute load average is the average number of processes that were waiting at any given instant over the past X minutes. So, for example, a 5 minute load average of 1.0 says that over the past 5 minutes there was normally 1 process ready to run that was being blocked. To read the /proc/loadavg file from the command line, you can use the cat command, like this: [eris@mozart eris]$ cat /proc/loadavg 0.43 0.28 0.14 2/124 30551 This shows a 1 minute load average of 0.43, a 5 minute average of 0.28 and a 10 minute average of 0.14. It is generally best if the load is less than 1, so this shows that while my system is doing a few things, it is not overburdened. You will have to decide for yourself what it means for your system to be "idle", but I would say that if the load average is less than 0.10 then it is fairly idle. You can find documentation about the /proc/loadavg file, and the other files in the /proc directories, in Chapter 5 of the Red Hat Enterprise Linux Reference Guide, which you can find here: http://www.redhat.com/docs/manuals/enterprise/ If you had a shell script and you wanted to read the load averages to determine whether or not to start the background job, you might use code like this: LoadAvg1=$(awk '{print $1 * 100}' /proc/loadavg) LoadAvg5=$(awk '{print $2 * 100}' /proc/loadavg) LoadAvg10=$(awk '{print $3 * 100}' /proc/loadavg) Threshhold=10 # This is .10 (the desired load average) times 100 if [ $LoadAvg5 -le $Threshhold ] ; then do_housekeeping fi This will start the do_housekeeping program if the system has been idle for 5 minutes. Notice that I multiplied the real load averages and the Threshhold by 100 to convert everything to integers since shell variables cannot be decimal numbers. Eris Caffee -- redhat-list mailing list unsubscribe mailto:redhat-list-request@xxxxxxxxxx?subject=unsubscribe https://www.redhat.com/mailman/listinfo/redhat-list
