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 IBM® i command to Start a Service Tool (STRSST). The Start Disk Management Operation (QYASSDMO) API provides a complete list of disk management configuration actions.
The Retrieve Disk 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 Disk 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 System i® Navigator disk management client, and all other applications that perform disk operations require a session to perform their requests. Therefore, it is important that applications use the End Disk management Session (QYASEDMS) API to release that session when all operations are complete.
Most disk management operations require a handle to a previously reserved configuration session. The Start Disk 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 Disk Management Status (QYASRDMS) API allows an application to check for status on a long-running operation. The End Disk Management Operation (QYASEDMO) API 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 about how to work with disk units, auxiliary storage pools, and storage protection, see the Disk management topic collection and the Recovering your system topic collection.
The disk management APIs are:
- Change ASP Activity (QYASPCHGAA) provides a set of actions that are used to quiesce the use of objects in the system ASP and the basic user ASPs (*SYSBAS), an ASP group or a UDFS ASP.
- Change Device Domain Data (QYASCHGDDD) does the initial setting or changes the contents of data set by a previous use of this API for the same data handle.
- Control ASP Access (QYASPCTLAA) enables exclusive use on an IASP.
- End Disk Management Operation (QYASEDMO) ends an active operation.
- End Disk Management Session (QYASEDMS) releases a client's reservation.
- Retrieve ASP Copy Information (QYASRTVINF) retrieves information about ASP copy descriptions or ASP sessions.
- Retrieve Device Domain Data (QYASRTVDDD) retrieves data that was previously set by the Change Device Domain Data (QYASCHGDDD) API.
- Retrieve Disk Information (QYASRDI) retrieves disk unit information.
- Retrieve Disk Management Status (QYASRDMS) retrieves status information for an active operation.
- Set Pointer Reset Boundary (QYASPPRBDY) sets a boundary for SYSBAS to IASP pointers.
- Start Disk Management Operation (QYASSDMO) requests the disk manager to perform an operation.
- Start Disk Management Session (QYASSDMS) reserves the disk manager for a specific client.