Information Technology - 2

Today I finished migrating my server to a new system. The LAMP-site consisting of 3 domains, which also runs an MTA and mailing list software, has been moved from Debian ‘woody’ to Debian ‘testing’ (alias ‘etch’). Insiders know that this is quite a big jump, leaving out the ‘sarge’ release. The main reason for this move was dying hardware: I expect either the graphics board or the SCSI-controller to be the cause, as they both are from 1998. Once in a while some system processes ended up in a segmentation fault, so I looked for a new (used) PC, which should become the successor.

It was a good opportunity to clean up the system, as the old one had its roots in a time when I made my first steps with Debian and wanted to maintain everything using ./configure && make && make install. Now, I want to avoid this and use the original Debian packages, because these days some commonly used additions are now officially available. Also, with Debian ‘testing’, there won’t be so gigantic delays between new releases of packages.

The interesting increments in the version numbers are: MySQL 4.0.20→5.0.18, Postfix 1.1.11→2.2.9, Courier-IMAP 1.4.3→3.0.8, Apache 1.3.31→2.0.55 and PHP 4.3.8→5.1.2.

I don’t have an iPod. I don’t need one. If I had one, I wouldn’t know what to do with it, except selling it. I don’t listen to music regularly anymore, for me, that time has been more than 10 years ago. I used a simple Sony Walkman, and all CDs I bought got copied over to music cassettes.

And I really don’t understand what’s the hype with podcasting. While I still understand high interest in music, I can’t imagine replacing music by spoken text in everyday life. People in underground trains and streetcars surely give their brains a rest and let their thoughts flow while listening to their favorite music. But can they really relax while following a (maybe even scientific) “radio broadcast” consisting of spoken text? Or have I misunderstood what a podcast is?

But, I have a weblog. And I’m on Linux. I’m still cool.

I got myself a “Super Multi DVD ReWriter”, namely the LG Electronics GSA-2166D, an external DVD burner using a USB 2.0 interface. I plugged it in and could use it immediately with GNU/Linux thanks to udev and the kernel modules scsi_mod, sr_mod (for SCSI CD-ROM drives) and usb_storage.

I want to use DVD-RAM as backup media, and it really works like a charm: I could create an ext2 filesystem on it by simply issuing the command

after which I could mount it and use it like a harddisk. The only drawback is when a large amount of data is written, the kernel is still busily writing data for up to 15(!) minutes after the copy process has finished in the user space!

Be careful when using such media with autofs. I experienced that when I simply began to copy data to /misc/dvdram without explicitly mounting the media before, autofs reaches its timeout during the transfer, which leads to a currupt filesystem. The manually executed e2fsck failed, all files went into lost+found!

Since I stuck two more PCI cards into my PC, stability problems aroused with my TV card: When the system load raised while watching TV in fullscreen, the system froze randomly. In addition, after resetting my PC, the 150GB Software-RAID-5 array had to resynchronize itself. As I restarted the TV app while the sync was running, the system froze a second time. Resetting again, two of the three RAID-5 partitions had been marked as failed, such that the automatic reassembling at boot time failed - I couldn’t even do the assembling by hand! My whole data was lost!!

Taken from the Gentoo Weekly Newsletter, 17 October 2005:

ext2/3 are the main filesystems for a large amount of users but what a lot of people don’t know is that you can get almost Reiser4 speed out of it without any of the instability they’d associated with Reiser4. One of the great features of ext2/3 is the ability to tune it by adjusting various parameters.

Let’s take some precautions, first of all by finding out if some of those parameter are already enabled, by running

(replacing XX with your drive and partition your ext2/3 filesystem resides in). If you don’t see tune2fs in the list then we can enable it, and just in case you do see ‘dir_index’ in ‘Filesystem features’ then you have either enabled it already or it was automatically enabled for you.

You are going to need a Gentoo LiveCD because changing parameters on mounted filesystems can cause problems, so in the interest of safety we are booting off the CD. At the start phase the Gentoo install system is booted into what’s called a “ramdisk” which is where the files needed are put into RAM to be used. mke2fs, tune2fs and other parts of the e2fsprogs package will be present at this stage.

Now let’s turn on the feature with

Do a filesystem check with

Do that on any ext2 or ext3 partition and then reboot. You should notice the difference straight away.