KrazyWorks» Monitoring

Simple Host Monitoring with SSH

Igor — Fri, 23 Sep 2011 04:10:06 +0000

Sometimes you just need something very simple to monitor a server or an application on a temporary basis. A basic ping monitor is fine, but it will only tell you if a server is responding on the network. It will not tell you if there is some other problem on the system. The script below relies on passwordless SSH setup to periodically log into the monitored nodes and check on their health by executing a local or remote script.

Changing Process CPU Affinity on Linux

Igor — Tue, 13 Sep 2011 20:58:37 +0000

Posted in Performance

A common real-life scenario: on a multi-CPU system Oracle processed have taken over and the system has ground to a crawl. The average system load is in double-digits and even logging in takes several minutes. The possible root causes for the problem can range from inefficient SQL queries (the common problem) to insufficient system resources. But at this point you just need to make the system a bit more responsive, so you can start troubleshooting.

Load-Testing HPC Linux Clusters with “stress”

Igor — Fri, 29 Apr 2011 00:43:56 +0000

Posted in Performance

The "stress" is a simple-to-use load generator for POSIX systems that I found very useful for stress-testing HPC clusters. The current version of the application is 1.0.4 and it was easy to compile and install. Stress can create configurable system load for CPU, memory, I/O, and disks. In the example below we ran "stress" on a SLES 11 HPC cluster with HP CMU 4.2 installed.

Installing Ganglia on RHEL

Igor — Mon, 21 Mar 2011 18:59:04 +0000

Posted in Performance

This is a quick follow-up to my earlier post about installing Ganglia from source on SLES. Here we will install Ganglia from precompiled RPMs on an RHEL server. The basic cluster setup for this example remains the same: two clusters: CLUSTER1 and CLUSTER2 with head nodes head_node1 and head_node2

Server and Network Monitoring with iPhone

Igor — Thu, 25 Feb 2010 22:53:42 +0000

Posted in Cell Phones Featured Monitoring

What is a Unix sysadmin doing with an iPhone, you ask? It was a birthday present, if that’s all right with you. I know, I should have gotten something odd with a beta version of ...

Copying Data: Are We There Yet?

Igor — Sun, 27 Dec 2009 23:12:12 +0000

Posted in Backups Networking Performance Veritas

I am sure this will sound familiar: you are copying a large amount of data - either locally or over the network - and you are wondering how long it will take and if there is a way to make things go faster.You may be surprised, but it does matter what type of files you are copying: 1Gb-worth of many small files will take considerably longer to copy than two 500Mb files. The hardware you are using is an important consideration, but it's not the only factor limiting data transfer speed.

Testing Filesystem Performance with Bonnie++

Igor — Fri, 10 Jul 2009 20:33:51 +0000

Posted in Disks and Volumes Filesystems Performance

Bonnie++ is a benchmark utility designed to test performance of hard drives and filesystems by simulating various types of disk I/O. Bonnie++ may be used to test local disks as well as network-mounted filesystems. It ...

Linux and High I/O Wait

Igor — Sun, 21 Dec 2008 04:07:08 +0000

Posted in Featured Performance

When you look at the CPU activity of your computer, one of the parameters is the iowait. This value shows how much time your CPU wastes while it is waiting for I/O operations for complete. ...

Linux performance tuning

Igor — Wed, 22 Aug 2007 19:40:19 +0000

Posted in Performance

Linux Performance Tuning April | May 2007 | by Jaqui Lynch Note: This is the second article in a two-part series. The first installment was published in the February/March issue. In last issue’s article I introduced basic Linux* ...

Simple network monitoring with ping

Igor — Tue, 11 Apr 2006 15:12:11 +0000

Posted in Monitoring Networking

In the Spring of 2005 Comcast experienced a major DNS outage. Since then many Comcast users have switched to DNS servers that belong to Verizon and other ISPs. Comcast started taking a lot of flak ...

Monitoring process CPU and memory usage

Igor — Thu, 15 Dec 2005 16:24:12 +0000

Posted in Processes

This article contains examples of using prstat to monitor CPU and memory utilization by individual processes and groups of processes. Example 1: Show CPU and memory usage by all processes called “*ora_smon_imanax*” The following prstat command will ...