Cacti: Simple system graphing for networks

Steve Wray put me on to Cacti the other day and I must say its pretty nice once you get over its slightly confusing interface. Cacti graphs statistics from network devices but unlike similar tools it does not try to do anything else. Think of it like bling for your network, good to look at, but maybe not that practical in a network emergency. But just like bling it is easy to put on and even better it is sure to impress your system admin friends, which in those hot and steamy server rooms we all want to do...

Installation is straightforward if you are running a typical LAMP stack (Linux, Apache, MySQL and PHP) but it can also run on a number of platforms including Windows if you are desperate. Cacti uses the PHP-SNMP extension to talk to SNMP agents on the network, keeps configuration settings in MySQL and stores accumulated network information as RRD files that get processed by RRDTool. Users can be configured with different access rights and devices/graphs can be clustered together in trees for easy viewing.

Click to enlarge screenshots

Two Scalix tips: Apache vhosts and keeping deleted mail

Scalix is a powerful, stable and soon to be almost completely open sourced email server. Unfortunately like many commercial products it is still a little rough round the edges when it comes to doing things outside of the supported method. Here is a couple of tips that may help you out when wanting to take Scalix "off-road" so to speak...

Sorting out Scalix tantrums

This morning after making some file changes and performing a server restart I found the Scalix 10 email server would not load. As I have never had to resolve major problems with Scalix determining the cause and solution to this error turned out to be a worthwhile experience.

Manually starting and stopping Scalix

According to the Scalix startup script (/etc/init.d/scalix) the service was successfully starting, but on closer inspection none of the actual processes were beginning. Unfortunately whilst the /etc/init.d/scalix script is a tidy way of controlling Scalix it does not provide any console logging to explain any issues that maybe encountered. For more useful output the two console commands that start/stop Scalix are:

Sharing disk partitions between Xen instances

Picture this, you have your Xen server and a couple of virtual instances configured and you are very happy. That is however until you want two or more of those instances to read or write files from the same disk partition. One way to get around this problem is to use a network file sharing protocol like NFS or CIFS and have one instance operate as a file server whilst the others connect as clients. Sure, a configuration like this works but it requires quite a bit of time to setup and more importantly it drains precious processor cycles as many extra, resource intensive processes must be run.

Enabling T3G on Suse Linux Enterprise Desktop

Mike Clements has been having some fun with Telecom's T3G mobile broadband service and getting it to work with Linux (namely Suse Linux Enterprise Desktop). He was using the Sierra Aircard 580 and information on how to get it working on Linux can be found on

For those who do not want spend time reading about the basics or learn by trial and error here is a step by step guide from Mike...

Enable LVM on software-RAID during a Suse installation

If you have tried setting up LVM on top of a LVM-enabled software-RAID partition during a standard Suse installation you may have hit a brick wall where the installer tells you that there are no available LVM partitions. This is a bug in the installer, it looks as if the LVM setup tool only checks physical partitions for LVM labels and ignores software-RAID partitions that have LVM labels.

Steve Wray has pointed out that you can get this functionality to work by creating a small physical partition and giving it an LVM label. The LVM setup tool will see this partition and allow the configuration to continue quite happily with the software-RAID partitions available for use. I have not tested this but I think it is worth giving a spin as the data integrity of RAID-1 coupled with the flexibility of LVM is a compelling combination (though performance maybe an issue).

Clueless Linux pundit of the week

There was a posting on the Linux forums that caught my attention mainly because its title and subsequent logic was so twisted that it was hard to ignore. Why Ubuntu Got It All Wrong is a fairly lengthy posting about how Ubuntu Linux, arguably the most successful Linux of the last few years, is completely wrong and should be viewed as a dismal failure. It is an interesting concept, Ubuntu is certainly showing signs of being too popular too fast, but the logic behind the argument is wrong. The weirdest statement made is that a 'revolutionary' Linux desktop should not resemble the current desktop (i.e. Windows/OSX) at all. In fact in the eyes of the author Ubuntu seems to fail because it is too conventional and the money invested by Mark Shuttleworth would have been better spent on experimental, never to be seriously adopted concepts like Project Looking Glass.

Novell vs Red Hat: A tale of two marketing atrocities?

NetworkWorld is running a good article on the competition between Novell and Red Hat in the Linux marketplace and how for once Novell may not be the worst marketing department in the game. The article makes some good points, Red Hat largely has its dominant position in the Linux market through being first and not because of tremendous marketing initiative or product direction. In fact for the last couple of years it kind of feels like they have been stationery bystanders compared to the frenetic activity within the Novell and Ubuntu camps recently.

Another tiny, low-cost Linux PC

The MicroClient Jr. looks really neat. It is not the most powerful machine in the world but in a space only slightly larger than your palm you get a fully functional PC complete with graphics, sound, ethernet, USB, CompactFlash and a 166mhz Pentium. Sure it is not the most powerful thing in the world but it is really cheap and ideal for console or light-weight X-environments or as a terminal services client running a traditional flat client. It has an expansion module for a 2.5" hard drive but by default it ships with a limited amount of memory rather than a bulky and expensive drive. It looks tidy, doesn't cost a fortune and runs Linux, what more can you ask for?

Novell promoting the Linux community

This is not a bad move from Novell. By setting up this Frapr mashup they have in some part begun to illustrate the depth and breadth of the Linux (mainly Suse) community. I put my name down just because of the rumours that there were Suse Linux licenses potentially up for grabs, I would not mind a Suse Linux Enterprise Server license as they are pretty pricey. Novell traditionally have been too old fashioned in their approach to Linux, hopefully this move and the growing quality of the Novell Open Audio podcast help in some way to break those old stodgy barriers down.