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Disk space usage in MySQL semi-sync cluster

In Managed databases, part of the disk space is reserved for service needs:

  • for the file system - 4% of the disk volume;
  • for the operating system, service components and logs - 8 GB.

The reserved portion of the disk space is not available to host databases.Keep this in mind when selecting a line of configurations.

You can monitor disk occupancy with disk occupancy notifications and metrics.For more information about metrics, see the Monitoring cluster, nodes, and databases MySQL semi-sync instructions .

When the cluster disk is 95% or more full, the cluster will go to DISK_FULL status and will be read-only.This is to prevent the cluster from being completely locked up or damaged due to lack of free space.To make the cluster read-write, scale the cluster and select a configuration with a disk size larger than the previous configuration.

Disk fullness notifications

Disk fullness notifications are sent to the Account Owner's email and to users who are subscribed to the "Services and Services" notification category.Notifications are sent when the disk is 80% and 95% full.