perfstat_cluster_disk Subroutine

Purpose

Retrieves the disk details of the cluster nodes.

Library

perfstat library (libperfstat.a)

Syntax

#include <libperfstat.h>

int perfstat_cluster_disk( name, userbuff, sizeof_userbuff, desired_number)

perfstat_id_node_t *name;
perfstat_disk_data_t *userbuff;
int sizeof_userbuff;
int desired_number;

Description

The perfstat_cluster_disk subroutine returns the list of disks in a perfstat_disk_data_t structure.

The perfstat_cluster_disk subroutine must be called only after you enable the cluster statistics collection by using the following perfstat API call:

perfstat_config(PERFSTAT_ENABLE | PERFSTAT_CLUSTER_STATS, NULL)

The cluster statistics collection must be disabled after you get the list of disks by using the following perfstat API call:

perfstat_config(PERFSTAT_DISABLE | PERFSTAT_CLUSTER_STATS, NULL)

To identify the total number of cluster disks in a specific node (in which the current node is participating), the following criteria must be specified:

The node name must be specified in the name parameter.
The userbuff parameter must be set to NULL.
The desired_number parameter must be set to 0.

To obtain the list of cluster disks in a specific node, the userbuff parameter and the desired_number parameter must be used.

Parameters

name.nodename or name.spec: Specifies the node name or the node ID for which the data must be returned.
userbuff: Specifies the memory area that must be filled with the perfstat_disk_data_t structure.
sizeof_userbuff: Specifies the size of the perfstat_disk_data_t structure.
desired_number: Specifies the number of structures to be returned.

Return values

The number of filled structures is returned upon successful completion. If unsuccessful, a value of -1 is returned and the errno global variable is set.

Error codes

The perfstat_cluster_disk subroutine fails because of one of the following errors:

EINVAL: One of the parameters is not valid.
ENOENT: The cluster statistics collection is not enabled by using the perfstat_config subroutine, the cluster statistics collection is not supported, or the specified node cannot be found.

Files

The libperfstat.h file defines standard macros, data types, and subroutines.