Unboxing ZTE MF-100

I won a ZTE MF-100 courtesy Dialog Axiata at their The Future, Today social media event held last week.See bellow for the unboxing and setting up photos. There is no how to for making it work with Linux or Snow Leopard because it works out of the box with no issues or caveats at all, enjoy πŸ™‚

PS: Thank you Dialog, you can follow them on Twitter @dialoglk

Samsung ML-1640 on Linux

I got my self a shiny new laser printer because the old Lexmark X1110 was getting old and giving little too many paper jams. I went with Samsung ML-1640 mainly because of it’s initial lower price, lower running costs and good reviews online. I had also read that the printer comes with Linux driver, that was one of the first I have seen.

To much to my surprise as soon as I plugged the printer Ubuntu recognized the printer and installed it, with in few seconds without any clicks or key presses the printer was ready for printing. I never bothered testing on Windows 7 but I’m sure I would have had to install drivers (Samsung claims it takes only 4 clicks).

However I ran to some trouble sharing the printer with Snow Leopard as the driver selected by Ubuntu needed to be used as a raw printer queue and I could get around how to set it up on Snow Leopard. Instead I flipped around the setup, I shared the printer as a raw printer queue and used the built in driver on Snow Leopard for the printer. I had to do the same for my notebook as well. Everything was working perfectly, finally πŸ™‚ . In the process I also figured out that Generic GDI driver works as long as the print job fits the printer memory (8 MB), if you send a larger job it will fail with nothing printed (but the printer receives the job).

For anyone wondering, on Linux the driver used is (automatically selected by Ubuntu) is Samsung ML-1640, SpliX V. 2.0.0 , which covers all capabilities of the printer (may be except for toner level).

I’m really happy with the printer, I think it was a very good purchase. I really like the idea the cartridge comes with a handle to push it into place. Then the fact that I can print the demo page by pressing and holding the reset/cancel button on the printer to get the toner level and other printer details. Only thing I miss is fully duplex printing, but with the lower cost I don’t mind working upto the printer to feed the paper when the printer is done printing one side of the pages.

Load balanced and High Availability cluster for your web site under USD 60 pm

Update 2009-09-02: Now I’m using a single Linode and a Xen VPS from my very own hosting service. This means the VPSes have one more thing less in common, hosting company.

Until recently I used one Linode VPS for hosting all my sites. On 26th March, there was a DDoS attack on one of the Linode customers in the Fremont Datacenter (where my node was as well). This made my sites inaccessible for couple of hours. This got me thinking, what could be done to mitigate such downtime. Answer of course is having a load balanced and high availability cluster. However I couldn’t afford 2 dedicated servers to do this, but I of course can afford 2 Linodes πŸ™‚ . I’ll try to explain how I set up a load balanced, high availability and shared nothing cluster using Linodes (you can use any VPS or dedicated server). I used two Linode 540 s for the job.

All of my web sites are either using PHP, Python or Perl. All of them are using MySQL as the database. Problems I had to solve were;

  1. replicate files across the nodes
  2. replicate databases across the nodes
  3. replicate session (PHP session variables) across the nodes

All the replication needs to be done securely, so I went for a SSH tunnel between the nodes of the cluster. Over which I’ll;

  1. use rsync to replicate/synchronize the document root
  2. use MySQL asynchronous replication (not a NDBCLUSTER) to synchronize data across the nodes
  3. use session_mysql PECL extension to store PHP session in MySQL database transparent to all applications

Check back next week when I’ll post with configuration examples on how I configured my server. If you are in a hurry above pointers are good enough to get you started.

Subversion to Git

My new year resolution was to ditch Subversion and move to Git. I switched to Git as my SCM for all my development work on new year day it self. I did hit some issues because my ignorance about how things are done with Git, however everything was fixed within the day. Now, 20 days later; I’m really happy that I did make the switch. Git has reduced development time greatly. No longer do I think about whether I should commit, wait for commit to finish for many minutes, or worry about overwriting someone’s work. Now I spend more time doing actual development than thinking about planning merges and commits.

I’ll blog about the few gotchas that I faced when I have time, hopefully soon. Development is fun again, thanks to Git. πŸ™‚

Use KernelCheck to build the latest kernel for debian/ubuntu

I recently found this awesome project called KernelCheck that allows you to build the latest Linux Kernel for your distribution. It requires very little interaction from the user and automatically optimizes the kernel to user’s needs. Currently it only supports Debian based distributions but support for RPM and Slackware based distributions is planned. KernelCheck is build around the AutoKernel idea by PinguinZ.

Building the Linux Kernel was never easier on Debian (and derivatives) before. I just compiled the, it wasn’t a pain at all.

v4l supports Avermedia PCI pure analog (M135A)

I bought a Avermedia PCI pure analog (M135A) recently (26th December) and to much to my delight it was just plug and play on my home media center running Debian testing with custom built Linux kernel 2.6.28 (Released on 24th December). TV tuner was working with no issues. All local TV channels we accessible :).Β  Even the remote was working (not all but the most critical ones like volume control and channel selection are working). Since my sound card didn’t have a mixer I had to use sox to redirect the sound from the TV tuner to the sound card. Running the following at start up did the job.

sox -r 32000 -w -t alsa hw:1,0 -t alsa hw:0,0

Just in case not all required modules are loaded in your case, the required modules to use this radio tuner are:

  • saa7134
  • saa7134_alsa
  • tda827x
  • tda8290

I’m really happy that now most of the hardware I can find in local shop is just plug and play on GNU/Linux. My kudos to v4l (video4linux) and the Linux kernel developers πŸ™‚ .

CUPS spool in devices with limited space

I was trying to print a large document, and it would never print. A small print job had no issues. To add to that I was printing a stupid PDF form that will only open with Acrobat Reader. The print job was passing through many places, VMWare guest, my notebook, and finally print server. I spent hours looking for what’s wrong.

Finally after many hours lost the issue was found to be lack of storage space in the print server; specifically print job spool was filling the disk.

I was unable to find a work around or a fix other than printing in smaller batches. I believe not many people come across this issue, IMHO this is not even worth fixing. I just blogged it for my own reference.

Going multi uplink

Last Friday I got a 2nd connection for my home-office. Now I have 1Mbit/s WiMAX uplink from Dialog Broadband and 512Kbit/s (Soon will be upgraded to 1Mbit/s) WiMAX uplink from Lanka Bell.

I have setup one of my old PCs as the router. I couldn’t find a single router with multi-uplink here in Sri Lanka, but PC router is more flexible, IMO. I’m running Debian on the router and using Shoreline Firewall aka Shorewall for firewalling and traffic shaping/control. It took a good few hours to setup mainly because I mixed up the ethernet interfaces πŸ˜€ . Shorewall documentation on multiple internet connections and traffic shaping/control by Tom Eastep helped me a lot in setting up my router.

Get Monit to repair your server!

Monit is an open source utility for managing and monitoring, processes, files, directories and filesystems on a UNIX system. Monit is capable of automatic maintenance and repair and can execute meaningful causal actions in error situations. It takes less than 15 minutes to setup and run this wonderful tool on most Unix servers. It also comes with a buit in web based service manager.

I personally prefer Monit over Nagios or ZABBIX. They are pain to install and not as flexible as Monit. AFAIK, Nagios only notifies and records events. It is unable to take a casual maintainance action such as restarting the service.

You will find some useful Monit scripts here.

My Kudos to the Monit team. I’m one happy Monit user πŸ™‚

Ubuntu 8.10 on Lenovo 3000 N200

Few hours ago I upgraded my Ubuntu 8.04 to 8.10. Upgrade it self was a smooth one. Download took around 1.5 hours and the installation was around 45 minutes. Ubuntu 8.10 Human theme looks sexy. New wireless driver for Intel 3945ABG has support for the LED indicator as well.

Only issues were:

  1. ALSA was locked while it’s being used by any application.
  2. OpenVPN Client was not routing all traffic through the tunnel (There was no obvious option to do add the routes in the NetworkManager)

ALSA issue was fixed with almost no effort but the solution for the OpenVPN client issue was not so obvious (at least for me).

Adding the following line to /etc/modprobe.d/alsa-base fixed the ALSA locking issue.

options snd-hda-intel model=lenovo

In NetworkManager 0.7 all traffic will not be routed through the tunnel if the OpenVPN serve pushes any routes or all of the rules that are pushed through are ignored. You can make NetworkManager to route all traffic through the tunnel by pushing a route similar to gw by adding a line similar to bellow to /etc/openvpn/openvpn.conf in the OpenVPN server

push "route gw"

or by making NetworkManager to ignore all routes pushed from the server. Check the “Ignore automatically obtained routes” checkbox in the Routes dialog in the VPN editing dialog (IPv4 Setting).

That’s it and my notebook is working better than it was before the upgrade. πŸ™‚

References: http://bugzilla.gnome.org/show_bug.cgi?id=552594 | https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.22/+bug/136810