Vertica Analytics Platform Version 10.1.x Documentation

DISK_STORAGE

Returns the amount of disk storage used by the database on each node. Each node can have one or more storage locations, and the locations can be on different disks with separate properties, such as free space, used space, and block size. The information in this system table is useful in determining where data files reside.

All returned values for this system table are in the context of the file system of the host operating system, and are not specific to Vertica-specific space.

The storage usage annotation called CATALOG indicates that the location is used to store the catalog. Each CATALOG location is specified only when creating a new database. You cannot add a CATALOG location annotation using CREATE LOCATION, nor remove an existing CATALOG annotation.

Storage Location Performance

The performance of a storage location is measured with two values: 

  • Throughput in MB/sec
  • Latency in seeks/sec

These two values are converted to a single number (Speed) with the following formula:

read-time = (1/throughput) + (1/latency)
  • read-time: Time to read 1MB of data
  • 1/throughput: Time to read 1MB of data
  • 1/latency: Time to seek to the data.

A disk is faster than another disk if its read-time is less.

Column Name Data Type Description
NODE_NAME

VARCHAR

Node name for which information is listed.

STORAGE_PATH

VARCHAR

Path where the storage location is mounted.

STORAGE_USAGE

VARCHAR

Type of information stored in the location, one of the following:

  • DATA: Only data is stored in the location.
  • TEMP: Only temporary files that are created during loads or queries are stored in the location.
  • DATA,TEMP: Both types of files are stored in the location.
  • USER: The storage location can be used by non-dbadmin users, who are granted access to the storage location
  • CATALOG: The area is used for the Vertica catalog. This usage is set internally and cannot be removed or changed.
RANK

INTEGER

Integer rank assigned to the storage location based on its performance. Ranks are used to create a storage locations on which projections, columns, and partitions are stored on different disks based on predicted or measured access patterns. See Managing Storage Locations.
THROUGHPUT

INTEGER

Integer that measures a storage location's performance in MB/sec. 1/throughput is the time taken to read 1MB of data.

LATENCY

INTEGER

Integer that measures a storage location's performance in seeks/sec. 1/latency is the time taken to seek to the data.

STORAGE_STATUS

VARCHAR

Status of the storage location, one of the following:

  • active
  • retired
DISK_BLOCK_SIZE_BYTES

INTEGER

Block size of the disk in bytes

DISK_SPACE_USED_BLOCKS

INTEGER

Number of disk blocks in use

DISK_SPACE_USED_MB

INTEGER

Number of megabytes of disk storage in use

DISK_SPACE_FREE_BLOCKS

INTEGER

Number of free disk blocks available

DISK_SPACE_FREE_MB

INTEGER

Number of megabytes of free storage available

DISK_SPACE_FREE_PERCENT

VARCHAR

Percentage of free disk space remaining