Backup

The organic design backups are created daily by User:Bender, compressed to .tgz and distributed over SSH to various other domains.

Backup related news items

• 20 November 2006 - regarding changeover to LZMA (.t7z)
• 23 November 2006 - 7z server backups which can be unpacked the same as our template in Debian Conversion
• 20 December 2006 - backup corruption in transfer

Backup list

The following list of backup files are currently being managed:

• od-wiki-db
• od-server-image
• od-access-log
• peer-logs
• peerd-win32
• nad-org
• nad-kb
• zenia-org
• zenia-docs-settings
• fowin-dunkley
• fowin-luck

About LZMA

LZMA is an extremely good compression method which compresses our backups to about one third of the size of the gzip or bzip. I have tested it with the free 7-zip file manager from www.7-zip.org and od-wiki-db-2006-11-20 is 268MB uncompressed, 54.9MB gzipped and only 21.7MB as a 7z! But I'm unable to get the Debian port to work due to dependency issues with low level C libraries that I don't want to mess with.

• I've found a standalone version at http://sourceforge.net/projects/p7zip and that's compressed it to 24.8MB, not quite as small as the windows one, but still very good.
• Using switches -t7z -m0=lzma -mx=9 has got it down to 21.1MB - slightly smaller than the windows version :-)

Statistics

7Zip is extremely good at compressing wiki data compared to other algorthims, perhaps due to compressing the history more efficiently, here's a size comparison for compressing a server image which is a standard linux file structure containing no database or web site content.

Compression	server image	wiki backup
none	517MB	269MB
7z	122MB (76%)	21.1MB (92%)
RAR	140MB (72%)	24.9MB (90%)
Bzip2	176MB (66%)	38.0MB (86%)
Gzip	197MB (62%)	54.5MB (80%)
Zip	197MB (62%)	54.5MB (80%)