This topic describes how a large amount of disk usage can cause disk locking for AnalyticDB for PostgreSQL instances in elastic storage mode.

Description

When the disk usage of a node of an AnalyticDB for PostgreSQL instance exceeds a specific threshold, the entire instance is locked. The storage capacity of each compute node determines whether an AnalyticDB for PostgreSQL instance can be locked.

  • If the storage capacity of each compute node is less than 600 GB, the instance is locked when the disk usage of a compute node exceeds 90%.

    You can view the Maximum Compute Node Storage Usage value in the console. When the value exceeds 90%, the instance is locked. For information about how to view the Maximum Compute Node Storage Usage value, see the View the disk usage of an instance section of this topic.

  • If the storage capacity of each compute node is greater than or equal to 600 GB, the instance is locked when the remaining disk space of a compute node is less than 60 GB.

    You can view the disk space of all nodes of the instance in the console. When the remaining disk space of a node is less than 60 GB, the instance is locked. For information about how to view the disk usage of the nodes of an instance, see the View the disk space of nodes section of this topic.

Instances become read-only after disk locking. To prevent business disruptions, you can upgrade instance specifications or add nodes before the disk usage reaches the threshold. For more information, see Change the specifications of compute nodes.

View the disk usage of an instance

  1. Log on to the AnalyticDB for PostgreSQL console.
  2. In the upper-left corner of the console, select the region where the instance resides.
  3. Find the instance that you want to manage and click its ID.
  4. In the Instance Status section of the Basic Information page, view the disk usage.
    • Maximum Compute Node Storage Usage: the disk usage of the node that contains the largest volume of data among all the nodes of the instance.
    • Instance Storage Usage: the average disk usage of all the nodes of the instance.

View the disk space of nodes

  1. Log on to the AnalyticDB for PostgreSQL console.
  2. In the upper-left corner of the console, select the region where the instance resides.
  3. Find the instance that you want to manage and click its ID.
  4. In the left-side navigation pane, choose Monitoring and Alerts > Node Monitoring.
  5. Click the Compute Nodes tab and view the Storage Used (MB) section.
    Move the pointer over the chart to view the disk space of compute nodes at a specific point in time.

Solution

If your AnalyticDB for PostgreSQL instance is locked due to overwhelming disk usage, you can use the following methods to unlock the instance:

  • Upgrade instance specifications (recommended)

    You can upgrade the specifications of the instance to add more disk space.

  • Increase the number of nodes

    You can add compute nodes to the instance. After this operation, the data of the instance is redistributed across all compute nodes, which may decrease the disk usage to a value lower than the threshold. If your instance remains locked after you add nodes, Submit a ticket.

For more information about how to upgrade instance specifications and increase the number of nodes, see Change the specifications of compute nodes.