Need to monitor Linux server performance? Try these built-in command and a few add-on tools. Most Linux distributions are equipped with tons of monitoring. These tools provide metrics which can be used to get information about system activities. You can use these tools to find the possible causes of a performance problem. The commands discussed below are some of the most basic commands when it comes to system analysis and debugging server issues such as:
- Finding out bottlenecks.
- Disk (storage) bottlenecks.
- CPU and memory bottlenecks.
- Network bottlenecks.
If you do not control or throttle end users, your server may run out of resources. Spammers, abuser and badly written bots can eat up all your bandwidth. A webserver must keep an eye on connections and limit connections per second. This is serving 101. The default is no limit. Lighttpd can limit the throughput for each single connection (per IP) or for all connections. You also need to a use firewall to limit connections per second. In this article I will cover firewall and lighttpd web server settings to throttle end users. The firewall settings can be applied to other web servers such as Apache / Nginx and IIS server behind PF / netfilter based firewall.
FreeBSD is just plain old good UNIX with rock solid networking stack. It is quite popular amongst hosting companies, ISPs, portals (such as Yahoo) and a few large financial institutions because of its reliability, robustness and performance.
A new version of the FreeBSD is scheduled for release next week (4-May-2009). A beta 2 was made available for download few weeks ago for final round of testing before the official launch.
Geolocation software is used to get the geographic location of visitor using IP address. You can determine country, organization and guess visitors location. This is useful for:
a] Fraud detection.
b] Geo marketing and ad serving.
c] Target content.
d] Spam fighting.
e] And much more.
mod_geoip is a Lighttpd module for fast ip/location lookups. In this tutorial you will learn about mod_geoip installation and php server side examples to determine visitors country.
MAC Filtering (layer 2 address filtering) refers to a security access control methodology whereby the 48-bit address assigned to each network card is used to determine access to the network. Iptables, pf, and IPFW can block a certain MAC address on a network, just like an IP. One can deny or allow from MAC address like 00:1e:2a:47:42:8d using open source firewalls. MAC address filtering is often used to secure LAN or wireless network / devices. Is this technique effective?
tail is one of the best tool to view log files in a real time (tail -f /path/to/log.file). The program MultiTail lets you view one or multiple files like the original tail program. The difference is that it creates multiple windows on your console (with ncurses). This is one of those dream come true program for UNIX sys admin job. You can browse through several log files at once and do various operations like search for errors and much more.
The second of two planned Release Candidates for the FreeBSD 7.2-RELEASE cycle is now available. ISO images for Tier-1 architectures are now available on most of the FreeBSD mirror sites.
The freebsd-update(8) utility supports binary upgrades of i386 and amd64
systems running earlier FreeBSD releases. Systems running 7.0-RELEASE,
7.1-RELEASE, 7.2-BETA1, or 7.2-RC1 can upgrade as follows:
# freebsd-update [...]
