Disk Management APIs

The Disk Management APIs provide basic control of disk units in the system. These APIs can be used to perform a variety of actions, such as changing the storage threshold for an auxiliary storage pool (ASP), adding a disk unit to an ASP, resuming protection on a disk unit, and formatting a disk unit. In general, these actions represent the disk management options available through the Work with Disk Units menu options from the i5/OS^(R) command to Start a Service Tool (STRSST). The Start DASD Management Operation (QYASSDMO) API provides a complete list of DASD management configuration actions.

The Retrieve DASD Management Information (QYASRDI) API and Open List of ASPs (QYASPOL) API return general information. These APIs do not require a disk management session handle.

The remaining APIs use a configuration session between the system disk manager and the configuration application. This session handle must be reserved using the Start DASD Management Session (QYASSDMS) API. The system disk manager supports only one active session at a time. The Work with Disk Units options under Dedicated Service Tools (DST) and System Service Tools (SST), the iSeries^(TM) Navigator disk management client, and all other applications performing disk operations require a session to perform their requests. Therefore, it is important that applications use End DASD management Session (QYASEDMS) to release that session when all operations are complete.

Most disk management operations require a handle to a previously reserved configuration session. The Start DASD Management Operation (QYASSDMO) API initiates an action. Most operations run to completion and return completion status on the start request. Some operations require a longer period of time in which to execute. These long-running operations return immediately, but must be checked for operation completion. The Retrieve DASD Management Status (QYASRDMS) API allows an application to check for status on a long-running operation. The End DASD Management Operation (QYASEDMO) provides a cancel mechanism. It is the responsibility of the application to know which operations return status immediately and which applications require additional status checking.

For information regarding how to work with disk units, auxiliary storage pools, and storage protection, see the Disk management topic and the Backup and Recovery book.

The Disk Management APIs are:

• Control ASP Access (QYASPCTLAA) enables exclusive use on an IASP. 
• End DASD Management Operation (QYASEDMO) ends an active operation.
• End DASD Management Session (QYASEDMS) releases a client's reservation.
• Retrieve DASD Information (QYASRDI) retrieves disk unit information.
• Retrieve DASD Management Status (QYASRDMS) retrieves status information for an active operation.
• Set Pointer Reset Boundary (QYASPPRBDY) sets a boundary for SYSBAS to IASP pointers. 
• Start DASD Management Operation (QYASSDMO) requests the disk manager to perform an operation.
• Start DASD Management Session (QYASSDMS) reserves the disk manager for a specific client.