Storage Devices

Storage Devices are attached to nodes and are used by modules running on the nodes to store database data and metadata. Once a storage device is added to a node, it can be assigned to a module. A device can only be attached to one module and cannot be transferred to another module. A module may have multiple storage devices. A storage device has a state that can be either OK or ERROR.

Commands

The storage device commands have the general form: MANAGE STORAGE DEVICE command [ parameters ].

STORAGE DEVICE ADD

This command adds one or more storage devices to the system. A storage device is added to a specific node. It is assigned to a module when the module is added in that node (see MODULE ADD above) and cannot be assigned to an existing module. This command is accepted only if the system is the SETUP state. Synopsis

MANAGE STORAGE DEVICE ADD [ FORCE ] ( ( 
	NODE node_name 
	NAME device_name 
	[ DESCRIPTION description ] 
	PATH path 
) [ , ... ] )

Parameters FORCE Optional parameter. By default, a storage device will not be added if it already belongs to a different Regatta system. If this option is specified, devices that belong to another Regatta system will be added. The device will be removed from the other system by force, and the impact on the other system is undefined. NODE Required parameter. The name of the node in which the storage device is added. NAME Required parameter. This name must be unique among all of the system’s storage devices, and will be used to identify the devices in queries and other commands. DESCRIPTION Optional parameter. Free text that is added to the storage device. PATH Required parameter. Specify the path to the device inside the node. When using shared networked storage devices, it’s important to specify a path that will not change if the node is restarted or if the module is moved to another node. One way to accomplish that is to use a path based on the device’s universally unique ID (UUID).

STORAGE DEVICE MODIFY

This command modifies the attributes of a storage device. Synopsis

MANAGE STORAGE DEVICE MODIFY device_name 
	PATH path 
	[ DESCRIPTION description ]

Parameters PATH Required parameter. Specify the local path to the device inside the node. When using shared networked storage devices, it’s important to specify the uuid-based path so that the module will be reconnected to the same device when it’s moved to another node. If the device is assigned to an active module, changing the path will take effect in the module only upon module restart. DESCRIPTION Optional parameter. Free text that is added to the storage device.

STORAGE DEVICE SHOW

This command shows the attributes of storage devices. Synopsis

MANAGE STORAGE DEVICE SHOW 
	[ FILTER STATE device_state ] [ DETAILED ]

MANAGE STORAGE DEVICE SHOW ATTR device_name [ FILTER ATTR attribute_name ]

This command has two variants:

A list of storage devices and their basic attributes
A detailed list of attributes for a specific storage device

Parameters FILTER Filter the result by some criterion. In the first variant of this command, nodes can be filtered by state. In the second variant, attributes can be filtered by attribute name. Currently the filtering is by exact match, no support for regular expressions. Only one filter can be specified. DETAILED Show a more detailed list of attributes for each module. See more details in the Output section below. Output For the first variant, the output of the command is tabular, with each row representing a storage device. The following table lists the columns of the output. If the DETAILED option is specified, then in addition to those columns, all the attributes listed below in the output of STORAGE DEVICE SHOW ATTR command are also included for each storage device. In this variant, only their current values are shown and not their set values.

Name	Type	Description
NAME	String	The name of the device
ID	Number	The identifier of the device. Assigned by Regatta.
STATE	String	The device state
PATH	String	The path to the device inside the node
NODE_NAME	String	The name of the node the device is attached to
MODULE_NAME	String	The name of the module the device is assigned to
CAPACITY	Number	The device capacity in bytes
DESCRIPTION	String	A description of the device (if exists)
LOCAL_NUMBER	Number	The ordinal number of the device inside the module it’s assigned to. Local numbering starts at zero.

For the second variant, the output of the command is tabular, with each row representing an attribute of the specified storage device. The following table lists the columns of the output.

Name	Type	Description
NAME	String	The name of the attribute
CURRENT_VALUE	String	The current value of the attribute
SET_VALUE	String	The set value of the attribute
REASON	String	If the current value differs from the set value, this column contains a reason for the difference. (For example, “Restart required”)

For each of the columns listed in the output of the first variant, there is a row in the second variant’s output.

SQL Specification

SQL Syntax Conventions

Data Types

SQL Functions and Operators

Data Definition Language (DDL) Commands

Data Manipulation Language Commands

Transaction Control Language Commands

Data Query Language

Hints

Managing Users

System Monitoring

System Management

Appendices

Storage Devices

Commands

STORAGE DEVICE ADD

STORAGE DEVICE MODIFY

STORAGE DEVICE SHOW

​Commands

​STORAGE DEVICE ADD

​STORAGE DEVICE MODIFY

​STORAGE DEVICE SHOW

Commands

STORAGE DEVICE ADD

STORAGE DEVICE MODIFY

STORAGE DEVICE SHOW