Kristof.Willen.be - Life in the trenches of the data center

I spent the last week in Budapest, attending the IBM AIX Technical University. Hundreds of presentations about AIX, Power, Storage and Tape, spread over 4 days in Budapest. The most interesting talk was about the new stuff in TSM6.2, where one of the most markant features was client upgrades through the TSM ISC. Client packages are pushed from the ISC to the TSM server, where they reside on a diskpool, ready for shipment to the clients. Currently only a Windows feature, but Unix will probably follow in the 6.3 release. There was unfortunately no possibility for a TSM certification, which meant I could not renew (or upgrade) my 5.4 certification.

There wasn't that much time for city sightseeing, though we did manage to get a small visit to the castle on the Buda side of the Lanchid bridge. Pretty nice city, and a good idea for a next city trip...

Het heeft iets meer voeten in de aarde gehad dan initieel verwacht, maar sinds gisteren hebben we dan toch een nieuw familielid. Jitta is een Landseer pup die er momenteel uitziet als een schattige witte pluizige teddybeer. Landseer honden zijn verwant aan de Newfoundlanders, groeien uit tot honden van zo'n 50tal kilo, en zijn algemeen bekend om hun vriendelijk & zacht karakter.

The possibilities of software synthesizers can be endless, and the more possibilities a program offers, the more complex it appears to any newbie. The guys at Propellerhead realized this, and put up a 34-part tutorial covering all aspects of Reason, with off course a large part dedicated to the Thor analogue oscillator.

Everyone sure knows fractals, the beautiful mathematical organic drawings. Because they appear similar at all levels of magnification, fractals are often considered to be infinitely complex. Natural objects that are approximated by fractals to a degree include clouds, mountain ranges, lightning bolts, coastlines or snow flakes. The most famous one is the Mandelbrot set, named to the French mathematician.

Programs like Fractint or its successor Xaos make fractal exploring within everyones reach. However, knowing where to zoom in, makes the difference between boring and exciting fractals. Here's a visual guide to fractal exploring, making you feel like Alice in Wonderland.

I just finished a very interesting case of a coredumping TSM client on Solaris. After investigation of the core dump, it seemed that the TSM client barfed over an erroneous inode. Some more diagnosis revealed indeed filesystem corruption, unfortunately on the root file system. Normally, one would boot from CDROM or issue a netboot, to correct the corruption, but it turned out the Jumpstart config of the host was really foobarred. I neither did have the time to correct the Jumpstart server config, or walk over to the data center to insert a Solaris DVD.

At times like that, I resort to little tricks in the bootsequence of Solaris : if you boot with boot -a -s, you can specify the location of the startup files. If you enter a /dev/null for the /etc/system file, the host will continue to boot, but with a read-only filesystem :

Rebooting with command: boot -a -s
Boot device: /pci@8,600000/SUNW,qlc@4/fp@0,0/disk@0,0:b File and args: -a -s
Enter filename [kernel/sparcv9/unix]:
Enter default directory for modules [/platform/SUNW,Sun-Fire-280R/kernel /platform/sun4u/kernel /kernel /usr/kernel]:
=> Name of system file [etc/system]: /dev/null
SunOS Release 5.10 Version Generic_118833-24 64-bit
Copyright 1983-2006 Sun Microsystems, Inc. All rights reserved.
Use is subject to license terms.
root filesystem type [ufs]:
Enter physical name of root device
[/pci@8,600000/SUNW,qlc@4/fp@0,0/disk@w500000e0155145d1,0:b]:
Booting to milestone "milestone/single-user:default".
Hostname: qwerty
SUNW,eri0 : 100 Mbps full duplex link up
Requesting System Maintenance Mode
SINGLE USER MODE

Root password for system maintenance (control-d to bypass):
single-user privilege assigned to /dev/console.
Entering System Maintenance Mode

After a few rounds of fsck's, the root filesystem turned out to be corrected, and only 2 files seemed to be impacted by the file system check. As the TSM client worked again, I could easily restore those from the backup.