29.12.22.4 The health_block_device Table

This table shows an equivalent of the df tool, executed every health_monitor.disk_sample_rate seconds, on the disk defined in health_monitor.disk_monitored.

mysql> select * from  performance_schema.health_block_device \G
*************************** 1. row ***************************
         DEVICE: /dev/mapper/ok-root
      TIMESTAMP: 2026-09-30 10:10:34
    TOTAL_BYTES: 75125227520
AVAILABLE_BYTES: 59197743104
    USE_PERCENT: 21.20
    MOUNT_POINT: /
*************************** 2. row ***************************
         DEVICE: /dev/mapper/ok-root
      TIMESTAMP: 2026-09-30 10:11:34
    TOTAL_BYTES: 75125227520
AVAILABLE_BYTES: 59197485056
    USE_PERCENT: 21.20
    MOUNT_POINT: /
*************************** 3. row ***************************
         DEVICE: /dev/mapper/ok-root
      TIMESTAMP: 2026-09-30 10:12:34
    TOTAL_BYTES: 75125227520
AVAILABLE_BYTES: 59197337600
    USE_PERCENT: 21.20
    MOUNT_POINT: /
*************************** 4. row ***************************
...

The health_block_device table has the following columns:

• DEVICE: Device name.

• TIMESTAMP: The time the data sample in this row was collected.

• TOTAL_BYTES: The total amount of storage on the device, in bytes.

• AVAILABLE_BYTES: The amount of available storage on the device, in bytes.

• USE_PERCENT: The percentage of disk space in use.

• MOUNT_POINT: Device mount point.