MySQL volume usage alert – database size mismatch
gzorzi
PROOP

a month ago

Hello,

I received the following alert:

“Volume of MySQL is 81% full in production”

However, after checking the database, I noticed a significant mismatch between the reported volume usage and the actual database size.

Here are the details:

  • The SQL dump of the database is approximately 10 MB

  • The total size of all tables and indexes (from information_schema.tables) is around 18–20 MB

  • innodb_file_per_table is ON

  • log_bin is OFF

Despite this, the MySQL volume is reported as almost full (around 80% usage, ~400 MB).

This suggests that the space is not used by application data, but likely by:

  • InnoDB redo/undo logs

  • historical file growth

  • internal MySQL or filesystem overhead within the volume

Could you please help clarify:

  1. What exactly is consuming the space in the MySQL volume?

  2. Whether there is a recommended way to reclaim unused space without recreating the service

  3. If recreating the MySQL service is the only way to reset the volume size in this case

At the moment the database itself is very small, so growing the volume does not seem justified unless strictly necessary.

Thank you for your support.

Best regards,
Gianpiero Zorzi

$10 Bounty

1 Replies

Railway
BOT

a month ago

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Status changed to Open Railway • about 2 months ago

darseen
HOBBYTop 5% Contributor

a month ago

The disk usage is most likely consumed by InnoDB redo/undo logs (pre-allocated files) or the System Tablespace (ibdata1), which grows but never shrinks automatically. The cleanest and most effective solution is to dump the data and recreate the MySQL volume/service. As there is no command to shrink ibdata1 in place.

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