Archive

Archive for December, 2011

Linux CPU usage and montioring using shell memcache and jquery

December 15th, 2011 No comments

Recently in a project where the application was deployed across multiple servers, the Client QA as well as Support Team wanted a better monitoring of all the servers in the production. It was too much to provide everybody with shell access and ask them to monitor using top. Well after a lot of digging through the wonderful search index of Google. And with insights from Paul Colby vide his article Calculating CPU Usage from /proc/stat, and various comments of Memcache usage through telnet along with the /dev/tcp socket connections it was just a matter of using some nifty shell processing before I could store each machine cpu values, loadavg, and running tasks as a json encoded string into memcache on one of the hosts with hostname as the key.
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PHP Sessions in Memcache – Locking Issues

December 9th, 2011 1 comment

Actually it is ages since I sat down to scribble something. Well this one could not be avoided. Hence here it is.

In one of our FTE projects, we had faced a complication that Memcached on one node was using 100% cpu and php-cgi was complainging that the same node was not permitting any more memcached connections. The configuration was as what all says, session.save_handler = memcache, session.save_path = “tcp://:11211,tcp://:11211,tcp://:11211″. It was giving jitters to the night support, that this used to happen at the worse time when most of the clients are using the application. And eventually that memcached needed to be restarted, kicking all users out and every one has to login back from the login page. Now during the past weeks it was so horrible that we marked a portion of the ramdisk from one least loaded nodes and used nfs to export this to all the nodes for a file based sessions store.
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