Depending on the operation you want to prevent being performed on a medium, you can mark it as either unreliable or unusable. To change a medium condition, you need to know its barcode.

Status “good” refers to the usable condition of a medium. It needs to be set manually by the administrator if the medium was previously defective but has been repaired and is ready to be put back to use. If you have manually marked the medium as unreliable or unusable, and you want to make it “good” (usable) again, you also need to mark it as such.

Preventing writing to an FSE medium

If you want to prevent further writing to a medium, but still need to access data on the medium in case no other medium copy is available, set its status to unreliable:

fsemedium --mark-unreliable Barcode

Once the medium is marked as unreliable, the medium can only be used for reading data.

Preventing reading from and writing to an FSE medium

If you want to prevent further use of a medium, set its status to unusable:

fsemedium --mark-unusable Barcode

Putting an FSE medium back into use

If there were errors detected on a medium, but now the medium is fixed and you want to put it back to use, you can remove its unreliable or unusable status:

fsemedium --mark-good Barcode

Once the medium is marked as “good” (usable), data on the medium can be read and the medium can be written to.

Closing medium volumes

By closing a medium volume you mark it as full and set its status in the Resource Management Database accordingly; therefore further writing to it is no longer possible. This operation also saves Fast Recovery Information to the end part of the medium volume and to the medium system volume, if it is present. If writing Fast Recovery Information to a medium fails, an appropriate warning is displayed.

For example, if you want to duplicate a medium which is almost full, you can close the original medium volumes in order to prevent further writing to it. For more details, see ”Duplicating media” on page 104.

Closing a medium volume is also useful in situations where the status of a whole FSE medium is set to unreliable due to a problem with a particular medium volume. Such problematic volume disables further use of other error-free medium volumes. When you close the unreliable medium volume and set the medium status to “good” (as described in ”Putting an FSE medium back into use” on page 120) you enable further use of other medium volumes on the same medium.

To close a medium volume, specify the medium barcode and volume number that you want to mark as full:

fsemedium --close-volume Barcode VolumeNumber

Recreating Fast Recovery Information from media

Recreating Fast Recovery Information (FRI) reads the complete contents of a medium volume and creates a new FRI file. The new file contains the same information but is usually more compact because it is created in a single pass.

Recreate FRI for the following:

•Open medium volumes for which on-disk FRI has been lost. The FRI will be stored to disk.

•Closed medium volumes that contain inconsistent or incomplete FRI.

120 Managing media