Using Removable Media Files

You can use the request command to manually create, write, and read files that do not use the disk cache for buffering the data. Files created in this manner are called removable media files.

Note - The request command bypasses the typical functions of the archiver.

Removable media files look like typical QFS files in that they have permissions, a user name, a group name, and size characteristics. However, their data does not reside in the disk cache. Therefore, you can create removable media files that are larger than the disk cache and write them to removable media cartridges.

The system creates an inode entry in the .inodes file for the file that you specify with the request command. The QFS file systems read that information from the inode entry. Multiple removable media files can reside on the same volume.

A removable media file that spans multiple volumes is called a volume overflow file. The volume overflow feature enables a single large file to span multiple volumes on multiple cartridges. The volume overflow feature is useful if you have very large files that exceed the capacity of their chosen media.

You must read and write removable media files sequentially. The QFS file system automatically mounts the requested volume if the volume resides in an automated library defined in the mcf file.

The presence of a removable media file on a volume prevents that volume from being recycled. The recycler expects that only archived files reside on the particular volume that is assigned for archiving. In addition, removable media files are never archived. Removable media files are not supported over NFS.

Creating a Removable Media or Volume Overflow File

Use the tplabel or odlabel command to label a tape or magneto-optical cartridge, respectively. See Labeling and Unlabeling Cartridges for details.

To create the file, issue the request command. At a minimum, use the following options:

request -m media-type -v vsn [vsn/vsn ...] [-l  /
vsn-file] input-file

Argument	Definition
media-type	The media type of the removable media cartridge. For information about valid media-type specifications, see mcf(4) in Sun QFS and Sun Storage Archive Manager Reference Manual.
vsn	The volume serial name (VSN) of the removable media cartridge. If you specify more than one VSN, you are creating a volume overflow file. You can specify up to 256 VSNs for volume overflow files. Use forward slash characters (`/`) to separate the vsn arguments.The VSNs specified should not be among the volumes that are used in a SAM-QFS environment for automated archiving. Archiving appends the next file to be archived to the end of the current data and moves the EOF label beyond the data.
vsn-file	An input file that contains a list of VSNs. When you have many VSNs, use an input file containing the list of VSNs
input-file	The file to be written to the removable media cartridge. This file must reside in a QFS file system.

Example 17-1 Create a Removable Media File

The following command creates a removable media file:

# request -m lt -v aaa rem1

For detailed examples of how to create removable media files, see request(1) in Sun QFS and Sun Storage Archive Manager Reference Manual.

Example 17-2 Create a Volume Overflow File

The following command creates a volume overflow file on three volumes:

# request -m lt -v TAPE01/TAPE02/TAPE03 large.file

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	Sun Storage Archive Manager 5.3 Configuration and Administration Guide Sun QFS and Sun Storage Archive Manager 5.3 Information Library