Using sar you can monitor performance of various Linux subsystems (CPU, Memory, I/O..) in real time. Using sar, you can also collect all performance data on an on-going basis, store them, and do historical analysis to identify bottlenecks. Sar is part of the sysstat package. This article explains how to install and configure sysstat package [...]
March 2011
For the past several months, I’ve been working on writing a book on the two great UNIX tools — Sed and Awk. I’ve spend lot of sleepless nights to make this book easy to read and understand with lot of examples. It is almost complete and the book will be released very soon. Once you [...]
If you are a sysadmin, you should secure your Apache web server by following the 10 tips mentioned in this article. 1. Disable unnecessary modules If you are planning to install apache from source, you should disable the following modules. If you do ./configure –help, you’ll see all available modules that you can disable/enable. userdir [...]
In our previous IPTables firewall series article, we reviewed how to add firewall rule using “iptables -A”. We also explained how to allow incoming SSH connection. On a high-level, it involves following 3 steps. Delete all existing rules: “iptables -F” Allow only incoming SSH: “iptables -A INPUT -i eth0 -p tcp –dport 22 -j ACCEPT” [...]
This is the 1st article in our new series on Linux performance monitoring and tuning. Linux system administrators should be proficient in Linux performance monitoring and tuning. This article gives a high level overview on how we should approach performance monitoring and tuning in Linux, and the various subsystems (and performance metrics) that needs to [...]
This article gives step by step instructions on how to install Apache 2 with mod_ssl. I prefer to install Apache from source, as it gives me more flexibility on exactly what modules I want to enable or disable, and I can also upgrade or apply patch immediately after it is released by the Apache foundation. [...]