Further proof, if any was needed, of the scalability of Bugzilla, mozilla.org’s most popular web application. About an hour ago, the 250,000th bug was filed in bugzilla.mozilla.org (“b.m.o.”), the oldest and largest known Bugzilla instance in the world.

The machine which runs b.m.o. is called “mecha”, and it runs all of the following services for mozilla.org single-handedly:

• Bugzilla
• The Mozilla Foundation’s internal Bugzilla
• Bonsai (this eats most of the CPU)
• Tinderbox (this eats most of the disk space)
• cvs-mirror (this eats most of the bandwidth, with Bugzilla running a close second)
• despot

Despite that, mecha’s specs are only that of a high-end Intel server:

• 2 x 2.8 GHz Xeon Hyperthreaded processors
• 90 GB of HD (in two partitions)
• 4 GB RAM
• Red Hat Linux Advanced Server release 2.1AS (Pensacola)

The Bugzilla installation itself has the following statistics:

• 4.7 GB database
• 250,000 bugs
• 152,000 attachments (3.3 GB)
• 2,195,000 comments (1 GB)
• 145,000 registered users
• 2,407,000 recorded changes

The Bugzilla application directory is 4 GB. 3.7 GB of that is duplicates data dating back to April 2001. (We don’t store the data which backs duplicates.cgi in the database; that was a mistake I made when I was young and foolish.)

We aren’t actually completely problem-free – we have run into a couple of scalability problems with bugmail. Bugs tend to go a bit funny when more than about 600 people or so need to be emailed when a change happens (and there’s currently 5 or 6 bugs on bugzilla.mozilla.org of which that is true). This should be fixed in the next release :-)