Built based on this
What is a bottleneck?
Types of bottlenecks
How to identify a bottleneck
ps -o pid,tt,user,fname,wchan -C apache (why is a process around and what is is waiting on)
ps -uapache -o wchan=WIDE-WCHAN-COLUMN,cmd
iftop http://www.thegeekstuff.com/2008/12/iftop-guide-display-network-interface-bandwidth-usage-on-linux/
disk io issues:
iostat -d -x
Linux 2.6.32-431.29.2.el6.x86_64 (web.x.com) 09/25/2014 _x86_64_ (16 CPU)
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 0.37 12.34 8.04 5.58 1299.72 143.13 105.96 0.81 59.82 9.55 13.01
http://bencane.com/2012/08/06/troubleshooting-high-io-wait-in-linux/
Reference: http://www.linux-tutorial.info/modules.php?name=MContent&pageid=84 http://www.gurkulindia.com/main/2013/03/help-me-to-find-the-linux-performance-bottleneck/ Pinpointing I/O bottlenecks on Linux http://www.cyberciti.biz/tips/linux-resource-utilization-to-detect-system-bottlenecks.html http://www.cloudiquity.com/2012/05/finding-disk-bottlenecks-on-linux/How to Monitor Apache Web Server Load and Page StatisticsHow to graph Apache Statistics on Cacti20 Command Line Tools to Monitor Linux Performance