Displaying Volume Status for an Aurora DB Cluster - Amazon Aurora

Displaying Volume Status for an Aurora DB Cluster

In Amazon Aurora, a DB cluster volume consists of a collection of logical blocks. Each of these represents 10 gigabytes of allocated storage. These blocks are called protection groups.

The data in each protection group is replicated across six physical storage devices, called storage nodes. These storage nodes are allocated across three Availability Zones (AZs) in the region where the DB cluster resides. In turn, each storage node contains one or more logical blocks of data for the DB cluster volume. For more information about protection groups and storage nodes, see Introducing the Aurora Storage Engine on the AWS Database Blog.

Use the aurora_show_volume_status() function to return the following server status variables:

  • Disks — The total number of logical blocks of data for the DB cluster volume.

  • Nodes The total number of storage nodes for the DB cluster volume.

You can use the aurora_show_volume_status() function to help avoid an error when using the aurora_inject_disk_failure() fault injection function. The aurora_inject_disk_failure() fault injection function simulates the failure of an entire storage node, or a single logical block of data within a storage node. In the function, you specify the index value of a specific logical block of data or storage node. However, the statement returns an error if you specify an index value greater than the number of logical blocks of data or storage nodes used by the DB cluster volume. For more information about fault injection queries, see Testing Amazon Aurora PostgreSQL Using Fault Injection Queries.

Note

The aurora_show_volume_status() function is available for Aurora PostgreSQL version 10.11. For more information about Aurora PostgreSQL versions, see Engine Versions for Amazon Aurora PostgreSQL .

Syntax

SELECT * FROM aurora_show_volume_status();

Example

The following example illustrates a typical result.

customer_database=> SELECT * FROM aurora_show_volume_status(); disks | nodes -------+------- 96 | 45