PUBLIC MARKS from lecyborg with tags ubuntu & debian

Munin is a simple to configure tool that make real nice graph about your server status. It can actually deal with almost any aspect of your server (load average, network cards status, CPU usage, memory usage, postfix, exim4, mysql ...) without spending much time in configuring it. Munin produce MRTG likes graph so you can easily see how your server health is going.

Not everyone knows about PHP's capabilities of making SSH connections and executing remote commands, but it can be very useful. I've been using it a lot in PHP CLI applications that I run from cronjobs, but initially it was a pain to get it to work. The PHP manual on Secure Shell2 Functions is not very practice or thorough for that matter, so I would like to share my knowledge in this how to, to make it a little less time consuming setting this up. In this article I'm going to assume that: * You're running Debian / Ubuntu If not, you will have to substitute the package manager aptitude with whatever your distribution provides * You're running PHP 5 If not, just replace php5 with php4 everywhere * You have basic knowledge of PHP & server administration * You already have PHP installed

Our intention is not to build a fail-safe system nor a HA-Linux. We are just using RAID-1 mirrored disks to make sure that the system can be restored easily if 1 disk crashes. The following has been tested only twice (hey, we've got other things to do). It did work for us, it might work for you. It might also make your rats go berserk or just blow your mind.

The system is equipped with 2 similar hard disks (they do not have to be the same but it helps if they are at least similar). The first disk is attached to the primary IDE as master, it will be referenced as /dev/hda. The second disk is attached to the secondary IDE also as master, it will be referenced as /dev/hdc.

Darkstat is a network statistics gatherer.Effectively, it’s a packet sniffer which runs as a background process on a cable/DSL router, gathers all sorts of useless but interesting statistics,and serves them over HTTP.

Since several years, I build my own network at home, running 2 to 7 machines at the same time (gateway, firewall, workstation, devstation, servers...). In my flat, it produce a lot of noise, take too many space and consume electricty. I decided to stop that, and to run my all network into a single machine, using virtual machine. The technology that convinced me is Xen.

Creating a Virtual Server - domU There are 3 options of what to run DomU on: 1. File Based Image 2. LVM Based 3. Physical Partition 1. A file based image is the quickest to setup, however has poor/terrible IO performance. The virtual server is limited to the initial size of the image created also. The file based Image can however be easily mounted in a rescue system, and easily backed-up. 2. LVM for domU is the industry standard. After the initial setup of LVM, as described here, it is a dream to manage. LVM partitions can be resized afterwards!!! Due to this "resizing" capability and flexibility, its use for Xen Virtual Servers is ideal. They also have much better IO performance than file-based. I dont know about mounting these partitions however in a rescue system. Something to try out... -). 3. Physical Partitions have the best IO, but are difficult to alter and inflexible.