CHECKTAPEPOS

The CHECKTAPEPOS option specifies whether the Tivoli® Storage Manager server validates the position of data blocks on tape.

The CHECKTAPEPOS option applies only to operations that use tape drives. It does not apply to non-tape, sequential-access device classes such as FILE. If the server information about position does not match the position that is detected by the drive, an error message is displayed, the transaction is rolled back, and the data is not committed to the database.

Using the CHECKTAPEPOS option, you can enable append-only mode for IBM LTO Generation 5 and later drives, and for any drives that support this feature. When it is enabled, the drive issues an error after it receives instructions to overwrite any data on the currently mounted volume. The Tivoli Storage Manager server repositions the tape to the correct block and continues writing data. Append-only mode provides added protection by preventing most data overwrite situations. If you are using a drive that supports this feature, you can validate data position on tape by using both Tivoli Storage Manager and the drive or you can enable one or the other.

Note: When you use SAN Tape acceleration functions in the fabric, set CHECKTAPEPOS to DRIVEonly or No to avoid false positive positioning errors. The Tivoli Storage Manager CHECKTAPEPOS server option does not require an append-only capable drive.

Changes to the CHECKTAPEPOS option affect mounts only after the update to the drive is complete.

The default is YES.

Syntax


>>-CHECKTAPEPOS--+-Yes-------+---------------------------------><
                 +-No--------+   
                 +-TSMonly---+   
                 '-DRIVEonly-'

Parameters

Yes: Specifies that the Tivoli Storage Manager server validates data position on tape. For drives that support append-only mode, this parameter specifies that Tivoli Storage Manager enables the drive to also validate the data position during each WRITE operation to prevent data overwrite. Yes is the default.
No: Specifies that all data position validation is turned off.
TSMonly: Specifies that the Tivoli Storage Manager server validates data position on tape. The server does not use append-only mode even if the drive supports the feature
DRIVEonly: Specifies that the Tivoli Storage Manager server enables append-only mode for drives that support this feature. The server does not validate the data position on tape.

Example

Validate data position on tape and enable append-only mode for a supported drive:

checktapepos yes