Before every deployment or any database changes, you always take a database backup. Sometimes, when you compare the size of that backup file to the database directory on disk (/var/lib/mysql), you’ll often see a big difference. A smaller dump and a larger data folder are perfectly normal. Your dump command isn’t wrong.

1. Why Dump Files Are Smaller Than Disk Usage

What mysqldump Exports

• Schemas: only the CREATE TABLE statements
  
  

• Raw row data: only the INSERT statements
  
  

• Nothing else: no indexes, no transaction logs, no engine metadata
  
  

What Lives in /var/lib/mysql/dbname/

• Data files
  
  

• InnoDB tablespaces (*.ibd)
  
  

• MyISAM data files (*.MYD)
  
  

• Indexes
  
  

• B-tree structures for fast lookups (*.MYI for MyISAM; built into .ibd for InnoDB)
  
  

• Logs & Overhead
  
  

• Undo/redo logs, binary logs (if enabled)
  
  

• Storage-engine metadata and page headers
  
  

• Unused fragmented space
  
  

• Gaps left inside data files by deletes or updates, not returned to the OS
  
  

Example : The MySQL dump is only 96MB and the size of the database directory path is 230MB (/var/lib/mysql/prod_orangehrm)

            dump = essentials

            data folder = essentials + indexes + logs + fragmentation.