vBulletin DB Size Optimization

My vBulletin forum runs on a single-server LAMP stack and the MySQL database has ballooned well beyond what I consider healthy. I need you to get the raw size back under control.

What I’m after
• Identify which tables are consuming the most space (user, post, and log tables are the usual suspects).
• Archive older data—please export it to a separate SQL file so I can store it offline yet restore it later if needed.
• Run the appropriate OPTIMIZE / ALTER commands (or other safe techniques) to reclaim disk space and defragment tables.
• Provide a short, plain-English report explaining what was done, how much space was saved, and any recurring maintenance tasks I should schedule.

Important notes
– Only table-level work is required; no code changes to vBulletin itself.
– The forum is live, so you’ll need to keep downtime to an absolute minimum.
– I’ve recently changed the site favicon; no action is needed there, but be aware of the recent file-cache flush when reviewing log sizes.
– Root or cPanel + phpMyAdmin access can be arranged once we agree on a start time.

If you’ve trimmed large vBulletin or similarly heavy forums before, I’d love to see a brief example. Fast, cautious work is the priority.