Tag Archives: ps

monitor Apache memory usage

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When looking at a webserver for memory usage, it’s important to consider the VSZ and RSS memory usage.

This little one liner gets the Total and Average VSZ and RSS usage as well as thread count, and prints those statistics every 5 seconds:

# while true; do ps auxfww | grep apache | grep -v -e cronolog -e grep | awk '{ vsum+=$5; rsum+=$6 } END { print "VSZ:", vsum, "(", vsum/NR, ") RSS:", rsum, "(", rsum/NR, ") Procs:", NR }'; sleep 5; done;
VSZ: 9896272 ( 341251 ) RSS: 1716216 ( 59179.9 ) Procs: 29
VSZ: 9547608 ( 340986 ) RSS: 1650100 ( 58932.1 ) Procs: 28
VSZ: 9546328 ( 340940 ) RSS: 1649044 ( 58894.4 ) Procs: 28
VSZ: 9861976 ( 340068 ) RSS: 1687968 ( 58205.8 ) Procs: 29
VSZ: 9868632 ( 340298 ) RSS: 1694496 ( 58430.9 ) Procs: 29
VSZ: 9853272 ( 339768 ) RSS: 1679112 ( 57900.4 ) Procs: 29
VSZ: 9853272 ( 339768 ) RSS: 1679264 ( 57905.7 ) Procs: 29
^C
#

So there are around 29 threads running right now on this server. The threads are using an average of 340MB per thread VSZ, and 59MB per thread RSS. The total of around 1.7GB of RSS looks good, on a machine with 8G physical memory.

show progress for dd

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By default dd is silent. It just copies whatever blocks you want from in to out. In order to see progress, send it a USR1 signal using kill.

Start a useless dd:

# dd if=/dev/zero of=/dev/null

In another terminal find the pid:

# ps aux | grep dd | grep -v grep
root      7784 90.5  0.0   2884   560 pts/9    R+   10:01   0:06 dd if /dev/zero of /dev/null
#
# kill -USR1 7784

The original window will now show this:

# dd if=/dev/zero of=/dev/null
14501614+0 records in
14501614+0 records out
7424826368 bytes (7.4 GB) copied, 16.2149 seconds, 458 MB/s

Then you can ctrl+c it to get the final output:

# dd if=/dev/zero of=/dev/null
14501614+0 records in
14501614+0 records out
7424826368 bytes (7.4 GB) copied, 16.2149 seconds, 458 MB/s
16888077+0 records in
16888076+0 records out
8646694912 bytes (8.6 GB) copied, 19.3507 seconds, 447 MB/s

This one liner will start your dd, then monitor it and output progress every 20 seconds. Once the dd is finished it will stop and give your shell back.

dd if=/dev/zero of=/dev/null & pid=$! && sleep 20s && while true; do i=`ps aux | awk '{print $2}' | grep ^$pid$`; if [ "${i:-a}" !=  "$pid" ]; then break; fi; kill -USR1 $pid; sleep 20s; done;