Tivoli Storage Manager support for append-only mode drives
Append-only mode is a tape drive feature that prevents data overwrite situations. When enabled, the drive issues an error after it receives a command to overwrite any data on the currently mounted volume. Append-only mode is a drive-specific behavior and can be enabled each time a tape is mounted. It can only be disabled when a tape is not mounted.
Enhancements to the Tivoli Storage Manager CHECKTAPEPOS server option allow supported drives to enable append-only mode beginning with fix pack levels 5.5.5, 6.1.5, and 6.2.2. You can enable append-only mode for IBM LTO Generation 5 and later drives, and for any drives that support this feature. Enabled drives will check for data overwrite before each WRITE operation and allow Tivoli Storage Manager to reposition tapes to the correct location and continue with writing data.
The Tivoli Storage Manager CHECKTAPEPOS server option does not require an append-only capable drive. When the TSMonly parameter is set, the Tivoli Storage Manager server validates the data position on tape.
The information below describes updates to the CHECKTAPEPOS option that allow append-only mode to be enabled.
The CHECKTAPEPOS server option description and parameters are updated:
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 using tape drives. It does not apply to non-tape, sequential-access device classes such as FILE or OPTICAL. If the server information about position does not match the position 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 drives that support this feature. When it is enabled, the drive issues an error after receiving 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 using both Tivoli Storage Manager and the drive or you can enable one or the other.
Changes to the CHECKTAPEPOS option only affect mounts after the update to the drive is complete.
The default for the CHECKTAPEPOS option is No for Tivoli Storage Manager Version 5.5 and 6.1 and Yes for Tivoli Storage Manager Version 6.2 and later.
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. This is the default value for Tivoli Storage Manager Version 6.2 and later.
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.
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.
Specifies that all data position validation is turned off. This is the default value for Tivoli Storage Manager Version 5.5. and 6.1.
In addition, the following commands are updated to support CHECKTAPEPOS:
- QUERY OPTION
Device drivers on Solaris and Windows operating systems must meet minimum required levels to enable append-only mode. The server will not enable append-only mode for older drivers. The following minimum levels are required:
Solaris: Version 22.214.171.124
Windows: Version 126.96.36.199
More support for:
Tivoli Storage Manager
Software version: 5.5, 6.1, 6.2
Operating system(s): AIX, HP-UX, Linux, Solaris, Windows
Reference #: 7019543
Modified date: 22 September 2010
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