Administrator's Guide

Access Modes for Storage Pool Volumes

Access to any volume in a storage pool is determined by the access mode assigned to that volume. You can change the access mode of a volume. The ADSM server can also change the access mode based on what happens when it tries to access a volume. For example, if the server cannot write to a read/write access volume, the server automatically changes the access mode to read-only.

The access modes are:

Read/write

Allows files to be read from or written to a volume in the storage pool.

If the server cannot write to a read/write access volume, the server automatically changes the access mode to read-only.

Read-only

Allows files to be read from but not written to a disk or tape volume.

Unavailable

Specifies that the volume is not available for any type of access by the ADSM server.

Destroyed

Specifies that a primary storage pool volume has been permanently damaged. Neither users nor system processes (like migration) can access files stored on the volume.

This access mode is used to indicate an entire volume that should be restored using the RESTORE STGPOOL or RESTORE VOLUME command. After all files on a destroyed volume are restored to other volumes, the destroyed volume is automatically deleted from the database. See "How Restore Processing Works" for more information.

Only volumes in primary storage pools can be updated to destroyed.

If you update a random access storage pool volume to destroyed, you cannot vary the volume online. If you update a sequential access storage pool volume to destroyed, ADSM does not attempt to mount the volume.

If a volume contains no files and the UPDATE VOLUME command is used to change the access mode to destroyed, the volume is deleted from the database.

Offsite

Specifies that a copy storage pool volume is at an offsite location and therefore cannot be mounted. Use this mode to help you track volumes that are offsite. ADSM treats offsite volumes differently, as follows:

• Mount requests are not generated for offsite volumes

• Data can be reclaimed or moved from offsite volumes by retrieving files from other storage pools

• Empty, offsite scratch volumes are not deleted from the copy storage pool

You can only update volumes in a copy storage pool to offsite access mode. Volumes that have the device type of SERVER (volumes that are actually archived objects stored on another ADSM server) cannot have an access mode of offsite.