Nov 132013

Reblogged from the Lanedo GmbH blog:

Tobin Daily Visits Screenshot

Tobin Daily Visits Screenshot

During recent weeks, I’ve started to create a new tool “Tobin” to generate website statistics for a number of sites I’m administrating or helping with. I’ve used programs like Webalizer, Visitors, Google Analytics and others for a long time, but there’re some correlations and relationships hidden in web server log files that are hard or close to impossible to visualize with these tools.

The Javascript injections required by Google Analytics are not always acceptable and fall short of accounting for all traffic and transfer volume. Also some of the log files I’m dealing with are orders of magnitudes larger than available memory, so the processing and aggregation algorithms used need to be memory efficient.

Here is what Tobin currently does:

  1. Input records are read and sorted on disk, inputs are filtered for a specific year.
  2. A 30 minute window is used to determine visits via unique IP-address and UserAgent.
  3. Hits, such as images, CSS files, WordPress resource files, etc are filtered to derive page counts.
  4. Statistics such as per hour accounting and geographical origin are collected.
  5. Top-50 charts and graphs are generated in an HTML report from the collected statistics.

There is lots of room for future improvements, e.g. creation of additional modules for new charts and graphs, possibly accounting across multiple years, use of intermediate files to speed up processing and more. In any case, the current state works well for giant log files and already provides interesting graphs. The code right now is alpha quality, i.e. ready for a technical preview but it might still have some quirks. Feedback is welcome.

The tobin source code and tobin issue tracker are hosted on Github. Python 2.7 and a number of auxiliary modules are required. Building and testing works as follows:

$ git clone
$ make # create tobin executable
$ ./tobin -n MySiteName mysite.log
$ x-www-browser logreport/index.html

Leave me a comment if you have issues testing it out and let me know how the report generation works for you. ūüėČ

Sep 022013

London Southwark Bridge

Next Friday I’ll be giving a talk on¬†Open Source In Business at the Campus Party Europe conference in the¬†O2 arena, London. The talk is part of the Free Software Track¬†at 14:00 on the Archimedes stage.¬†I’m there the entire week and will be happy to meet up, so feel free to drop me a line in case you happen to be around the venue as well.

The picture above shows the London¬†Southwark Bridge¬†viewed from Millenium Footbridge with the London Tower Bridge in the background. Last week’s weather has been exceptional for sightseeing in London, so there were loads of great chances to visit that vast number of historical places and monuments present in London. My G+ stream has several examples of the pictures taken. I honestly hope the good weather continues and allows everyone to enjoy a great conference!

Update: The slides and video of the talk are now online here: Open Source In Business

Feb 082013

Determine candidates and delete from a set of directories containing aging backups.
As a follow up to the release of last December, here’s a complimentary tool we’re using at Lanedo. Suppose a number of backup directories have piled up after a while, using or any other tool that creates time stamped file names:

 drwxrwxr-x etc-2010-02-02-06:06:01-snap
 drwxrwxr-x etc-2011-07-07-06:06:01-snap
 drwxrwxr-x etc-2011-07-07-12:45:53-snap
 drwxrwxr-x etc-2012-12-28-06:06:01-snap
 drwxrwxr-x etc-2013-02-02-06:06:01-snap
 lrwxrwxrwx etc-current -> etc-2012-12-28-06:06:01-snap

Which file should be deleted once the backup device starts to fill up?
Sayepurge parses the timestamps from the names of this set of backup directories, computes the time deltas, and determines good deletion candidates so that backups are spaced out over time most evenly. The exact behavior can be tuned by specifying the number of recent files to guard against deletion (-g), the number of historic backups to keep around (-k) and the maximum number of deletions for any given run (-d). In the above set of files, the two backups from 2011-07-07 are only 6h apart, so they make good purging candidates, example:

 $ -o etc -g 1 -k 3 
 Ignore: ./etc-2013-02-02-06:06:01-snap
 Purge:  ./etc-2011-07-07-06:06:01-snap
 Keep:   ./etc-2012-12-28-06:06:01-snap
 Keep:   ./etc-2011-07-07-12:45:53-snap
 Keep:   ./etc-2010-02-02-06:06:01-snap

For day to day use, it makes sense to use both tools combined e.g. via crontab. Here’s a sample command to perform daily backups of /etc/ and then keep 6 directories worth of daily backups stored in a toplevel directory for backups:

 /bin/ -q -C /backups/ -o etc /etc/ && /bin/ -q -o etc -g 3 -k 3

Let me know in the comments what mechanisms you are using to purge aging backups!


The GitHub release tag is here: backups-0.0.2
Script URL for direct downloads:

Usage: [options] sources...
  --inc         merge incremental backups
  -g <nguarded> recent files to guard (8)
  -k <nkeeps>   non-recent to keep (8)
  -d <maxdelet> maximum number of deletions
  -C <dir>      backup directory
  -o <prefix>   output directory name (default: 'bak')
  -q, --quiet   suppress progress information
  --fake        only simulate deletions or merges
  -L            list all backup files with delta times
  Delete candidates from a set of aging backups to spread backups most evenly
  over time, based on time stamps embedded in directory names.
  Backups older than <nguarded> are purged, so that only <nkeeps> backups
  remain. In other words, the number of backups is reduced to <nguarded>
  + <nkeeps>, where <nguarded> are the most recent backups.
  The puring logic will always pick the backup with the shortest time
  distance to other backups. Thus, the number of <nkeeps> remaining
  backups is most evenly distributed across the total time period within
  which backups have been created.
  Purging of incremental backups happens via merging of newly created
  files into the backups predecessor. Thus merged incrementals may
  contain newly created files from after the incremental backups creation
  time, but the function of reverse incremental backups is fully
  preserved. Merged incrementals use a different file name ending (-xinc).
See Also – deduplicating backups with rsync

Dec 012012

Due to popular request, I’m putting up a polished version of the backup script that we’ve been using over the years at Lanedo to backup our systems remotely. This script uses a special feature of rsync(1) v2.6.4 for the creation of backups which share storage space with previous backups by hard-linking files.
The various options needed for rsync and ssh to minimize transfer bandwidth over the Internet, time-stamping for the backups and handling of several rsync oddities warranted encapsulation of the logic into a dedicated script.


The GitHub release tag is here: backups-0.0.1
Script URL for direct downloads:


This example shows creation of two consecutive backups and displays the sizes.

$ -i ~/.ssh/id_examplecom # create backup as bak-.../mydir
$ -i ~/.ssh/id_examplecom # create second bak-2012...-snap/
$ ls -l # show all the backups that have been created
drwxrwxr-x 3 user group 4096 Dez  1 03:16 bak-2012-12-01-03:16:50-snap
drwxrwxr-x 3 user group 4096 Dez  1 03:17 bak-2012-12-01-03:17:12-snap
lrwxrwxrwx 1 user group   28 Dez  1 03:17 bak-current -> bak-2012-12-01-03:17:12-snap
$ du -sh bak-* # the second backup is smaller due to hard links
4.1M    bak-2012-12-01-03:16:50-snap
128K    bak-2012-12-01-03:17:12-snap
4.0K    bak-current
Usage: [options] sources...
  --inc         make reverse incremental backup
  --dry         run and show rsync with --dry-run option
  --help        print usage summary
  -C <dir>      backup directory (default: '.')
  -E <exclfile> file with rsync exclude list
  -l <account>  ssh user name to use (see ssh(1) -l)
  -i <identity> ssh identity key file to use (see ssh(1) -i)
  -P <sshport>  ssh port to use on the remote system
  -L <linkdest> hardlink dest files from <linkdest>/
  -o <prefix>   output directory name (default: 'bak')
  -q, --quiet   suppress progress information
  -c            perform checksum based file content comparisons
  -x            disable crossing of filesystem boundaries
  --version     script and rsync versions
  This script creates full or reverse incremental backups using the
  rsync(1) command. Backup directory names contain the date and time
  of each backup run to allow sorting and selective pruning.
  At the end of each successful backup run, a symlink '*-current' is
  updated to always point at the latest backup. To reduce remote file
  transfers, the '-L' option can be used (possibly multiple times) to
  specify existing local file trees from which files will be
  hard-linked into the backup.
 Full Backups:
  Upon each invocation, a new backup directory is created that contains
  all files of the source system. Hard links are created to files of
  previous backups where possible, so extra storage space is only required
  for contents that changed between backups.
 Incremental Backups:
  In incremental mode, the most recent backup is always a full backup,
  while the previous full backup is degraded to a reverse incremental
  backup, which only contains differences between the current and the
  last backup.
 RSYNC_BINARY Environment variable used to override the rsync binary path.
See Also

Testbit Tools – Version 11.09 Release

Nov 232012

For a while now, I’ve been maintaining my todo lists as backlogs in a Mediawiki repository. I’m regularly deriving sprints from these backlogs for my current task lists. This means identifying important or urgent items that can be addressed next, for really huge backlogs this can be quite tedious.

A SpecialPage extension that I’ve recently implemented now helps me through the process. Using it, I’m automatically getting a filtered list of all “IMPORTANT:”, “URGENT:” or otherwise classified list items. The special page can be used per-se or via template inclusion from another wiki page. The extension page at has more details.

The Mediawiki extension page is here:

The GitHub page for downloads is here:

May 152012
Multitasking Mind


Like every year, I am driving to Berlin this week to attend LinuxTag 2012 to attend the excellent program. If you want to meet up and chat about projects, technologies, Free Software or other things, send me an email or leave a comment with this post and we will arrange for it.

May 092011
Multitasking Mind


Like every year, I am driving to Berlin this week to attend LinuxTag 2011 to attend the excellent program. If you want to meet up and chat about projects, technologies, Free Software or other things, send me an email or leave a comment with this post and we will arrange for it.