Posts about sysadmin (old posts, page 4)

2008-04-04 11:41

This is why Linux is not ready for the desktop

If you delete the empty directory /var/lib/xkb, then enable the KDE keyboard layout switcher, the up-arrow key works like print-screen.

At least on my box it does. It took me a month to figure it out.

2008-03-11 14:23

Good News: Linux gives life to old hardware. Bad News: Maybe in some cases it shouldn't.

I was in one of my customer's datacenters the other day, and while I do most work remotely, I had to take this opportunity to take some snapshots of their proxy server.

This post is just a bit of fun. This is not supposed to be their server, it was just a stopgap measure because of multiple hardware failures. This is a large, well managed company, and this irregular situation will be fixed soon. And anyway, it is working just fine.

As you know, Linux can do that kind of job easy without much hardware requirements. After all, it has to handle at most about 3Mbps of data, and this box has 2GB of ram, so there's plenty of room for a speedy cache.

So, let's go for some good news/bad news.

Good news: It's a true-blue IBM Server! Bad news: It's a IBM Netfinity 5000 (model 3Ry)!

2110.0.Imagen011

Here is some tech info from IBM about it.

Good news: It has 2 CPUs! Bad news: They are two 450Mhz Pentium II CPUs.

Good News: it has hot-swappable SCSI discs! Bad news: you have no discs for that controller, so we will use this 8GB IDE (PATA) disk!

2108.0.Imagen013

And will leave it just sitting there by the CD unit, besides the huge gaping hole in the front where the SCSI discs would be.

Bad News: it has a tendence to overheating! Good News: You have a place to keep your coffe warm!

2109.0.Imagen014

2008-03-07 07:43

New qmail plugin idea: overload

It should not happen but it does: Your qmail server is overloaded. Maybe you are under a DOS attack, or there is a reason why you are getting 10x your usual amount of mail.

But then you start seeing how your "not preprocessed" queue starts growing, and growing...

This can also mean things like clamav or spamassassin, which need to check the mail before it gets queued are not keeping up with the mail flow, or maybe some IO performace issue.

But what can you do righ now to fix it?

Well, you can disable spamassassin, or, in extreme cases, shutdown SMTP so the system has a chance to catch its breath so to speak.

Of course, closing SMTP means your own users can't send email either, which sucks.

Now there is a lighter alternative: shutdown SMTP for those who are not your users.

Here's the trivial code, implemented as a SPP plugin, fit to be used in the [mail] section:

#!/bin/dash

if [ -f /var/qmail/control/overloaded ]
then
      if [ -z "$SMTPAUTHUSER" ]
      then
              echo R451 Temporary Failure: Server overload
              echo overload: $PPID Temporary Failure: Server overload >&2
      fi
fi

And if you are daring and want to make your system self-correcting, maybe you should cron something like this:

* * * * * if [ `qmail-qstat  | tail -1 | cut -d: -f2` -gt 100 ];\
then touch /var/qmail/control/overloaded ;\
else rm -f /var/qmail/control/overloaded; fi

I will probably code it again in C and make it part of ra/plugins.

2008-01-24 17:47

Yes, Xandros was horrible. But this ubuntu thing is working out nicely!

As I said before, the bastardized Xandros [1] sucked. In fact, I managed to destroy it. So I decided to switch to another distro. Any distro.

Enter eeeXubuntu, a eee-tuned Xubuntu [2].

Since I prefer KDE to XFCE, I started hacking at it, and produced, IMVHO, a much nicer thing.

keee.png

As you can see, it takes slightly less space than eeeXubuntu's default, and a whooping 1GB less than the default distro.

How did I do it? First, by deciding what I wanted.

  • No OpenOffice. Koffice is enough to read docs, then there is Google docs, and I produce my texts using docutils
  • No printing. I have not used a printer in 5 years. What are the odds I will use one from the eee?
  • wicd for network configuration. It works for wireless/wired/encrypted and has no problem whatsoever reconnecting after suspend.
  • yakuake for terminal. It uses the least screen-space possible: none if you are not using it.
  • Firefox + Flash (I would use Konqueror, if flash9 had not broken it)
  • Kmail + Akregator for mail and RSS

It works great, boots in 35 seconds (and I have not tuned that, yet).

Here's the list of installed packages and here's the list of repos I am using

Maybe someone more enterprising will make a real distro out of it.

[1] Which is itself a bastardized Debian etch.
[2] Which is a XFCE-tuned ubuntu

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