After performing some security related OS updates, i was receiving from LDAP all sort of strange errors. Like, when you logged on the ldap server as a regular ldap user (not system user) the regular user@host:~$ prompt changed to:
I have no name!@host:~$
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This article will show how you can rebuild any debian package. You might need to rebuild a package for various reasons: add/remove some compilation options, make some changes to the sources, or compile a newer version from testing/sid into stable, etc. Regardless of your reason, this can be done very easy using debian tools.

First you will need to have some basic debian building tools installed:
apt-get install devscripts build-essential Read the rest of this entry »

According to tune2fs manual, reserved blocks are designed to keep your system from failing when you run out of space. Its reserves space for privileged processes such as daemons (like syslogd, for ex.) and other root level processes; also the reserved space can prevent the filesystem from fragmenting as it fills up. By default this is 5% regardless of the size of the partition.

On large partitions (250GB drives and up are quite common these days), the default 5% reserved space can be quite a lot (12.5Gb in my example). For ext3 partitions you can tune this parameter by using tune2fs with the parameter -m. For ex. to decrease this to 3% you would run (for ex. on /dev/sda1):
tune2fs -m3 /dev/sda1
You should be very careful when ‘playing’ with this parameter and be sure you know what you are doing before changing this value.

It seems that the Debian team doesn’t like to release minor versions anymore. After Debian 4.0 (code name “Etch”) released last year, the next Debian release (code name “Lenny“) will be numbered as Debian 5.0 as announced yesterday by Marc Brockschmidt: “For reading this far, you receive the small reward of the knowledge that Lenny will be shipped as Debian 5.0.”

Also interesting enough he mentioned that Lenny might be released with KDE4:
“There may be a possibility to include KDE 4 in Lenny. The efforts on KDE 4.1 have been quite promising and seem to be leading to a desktop environment which can fully replace KDE 3. The KDE team will provide betas and release candidates of the 4.1 release in experimental. In the event that KDE 4.1 is on time, and there are no major issues, an upload to unstable in order to include it in Lenny is possible.”

The development of Debian GNU/Linux 5.0 seems to be on track and the final release is still expected in September 2008.

Debian provides security updates for old stable releases for one year after a new distribution has been released. Yesterday, Debian announced that the support for Debian 3.1 (sarge) is coming to an end this month, as etch was released last year in April, sarge will be supported until March 2008.

Anyone still running Debian sarge, should really be thinking seriously to finally update to etch asap.

Debian’s Official Announcement: http://www.debian.org/News/2008/20080229

This document describes how to install and use sshfs, a FUSE based filesystem that uses SSH to mount remote folders. Since it is based on FUSE (userspace filesystem framework for Linux) your kernel will need to have the fuse module available. FUSE is included in kernel newer than 2.6.14, so I will assume that you will have it already included in your kernel.

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“The Debian project is pleased to announce the third update of its stable distribution Debian GNU/Linux 4.0 (codename etch). This update mainly adds corrections for security problems to the stable release, along with a few adjustment to serious problems.

Those who frequently install updates from security.debian.org won’t have to update many packages and most updates from security.debian.org are included in this update.”

Note: this is true . I’ve not even noticed this and seen it as a minor apt upgrade

Release Announcement: http://www.debian.org/News/2008/20080217

A complete list of all accepted and rejected packages together with rationale is on the preparation page for this revision: http://release.debian.org/stable/4.0/4.0r3/

If you have seen an error like “Fatal Error: PHP Allowed Memory Size Exhausted” in apache logs or in your browser, this means that PHP has exhausted the maximum memory limit. This post will show 3 different ways on how you can increase the php memory limit and also explain when you should use them.

First, let’s see where is this limit coming from. Normally you will see from the error message what is the actual limit, as this will look like:
PHP Fatal error: Allowed memory size of X bytes exhausted (tried to allocate Y) in whatever.php
The default value might differ depending on what php version and linux distribution you are running, but normally this will be set to either 8M or 16M. For example on my debian etch, running on php 5.2 this is set by default at 16M.

In order to identify the current value on your system, look inside your php.ini and search for memory_limit:
memory_limit = 16M ; Maximum amount of memory a script may consume (16MB)

There are three ways to change this value, the obvious way - changing the global value from php.ini, but also an individual method to change it just for a script, or folder. Read the rest of this entry »

Normally MySQL replication will stop whenever there is an error running a query on the slave. This happens in order for us to be able to identify the problem and fix it, and keep the data consistent with the mater that has sent the query. You can skip such errors, even if this is not recommended, as long as you know really well what are those queries and why they are failing, etc.

For example you can skip just one query that is hanging the slave using:
mysql>SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1; START SLAVE;

There might be cases where you will want to skip more queries. For example you might want to skip all duplicate errors you might be getting (output from show slave status;):
"1062 | Error 'Duplicate entry 'xyz' for key 1' on query. Default database: 'db'. Query: 'INSERT INTO ..."

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The Unix find command is a very powerful tool, and this short post is intended to show how easy you can achieve something that might look complicate: to find all the files of a particular size. Let’s assume you are searching for all the files of exactly 6579 bytes size inside the home directory. You will just have to run something like:

find /home/ -type f -size 6579c -exec ls {} \;

As units you can use:

• b - for 512-byte blocks (this is the default if no suffix is used)
• c - for bytes
• w - for two-byte words
• k - for Kilobytes (units of 1024 bytes)
• M - for Megabytes (units of 1048576 bytes)
• G - for Gigabytes (units of 1073741824 bytes)

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