Managing a Mixed-Media Library

With mixed-media, ACSLS supports a mixture of tape drive and media (cartridge) types in the same library. ACSLS mixed-media support prevents the robot from mounting incompatible media types in a tape drive. For example, in an SL8500, the robot will not mount an LTO cartridge in a T10000 tape drive.

ACSLS mixed-media support requires Media ID labels with media characters on cartridges.

Note:

Refer to the ACSLS Product Information Guide for the current list of drive types, media types and drive-to-media compatibility supported.

ACSLS has limited knowledge of the recording format used on cartridges. ACSLS does not have access to the data path to tape drives, so ACSLS cannot detect and prevent recording format incompatibilities. However, recent T9840 and T10000 tape drives report the media recording format on a dismount. ACSLS saves this information in the database, and it can be displayed with the command:

display volume [vol_id(s)] –f recording_format_family recording_format_model

For more information, see display volume.

Displaying the ACSLS Mixed-Media Settings

The drives_media.sh utility displays the drive types, media types, and drive-to-media compatibility settings currently supported by ACSLS. As support is added for new drives and media, they are displayed.

To display the ACSLS Mixed-Media settings, enter:

drives_media.sh

The information writes to the screen (standard output).

To output the ACSLS Mixed-Media settings to files in the /tmp directory, enter:

drives_media.sh -f

The information will be written to three files. (If the files already exist, they will be overwritten.)

/tmp/drive_types.txt 
/tmp/media_types.txt 
/tmp/media_compatibility.txt

Mixed-Media Restrictions for SCSI-Attached LSMs

Note the following restrictions for SCSI-attached LSMs:

Because some tape drives do not support dynamic write-protect settings are through the control path, you must use caution when mounting cartridges using the ‘read-only' option. All StorageTek drives support this feature. For non-StorageTek drives, you are advised to confirm that dynamic write-protection is supported. Specifically, LTO drives do not support the “read-only" option.

Unless the drive supports this feature, you run the risk of losing data on cartridges that you assumed are to be mounted with the write-disable protection of a read-only mount.
Automatic-cleaning operations in SCSI-attached libraries is handled by the library microcode and not by ACSLS. The library control panel provides a menu for users to enable library control of automatic-cleaning operations. For more information, see your library documentation.
You can select a normal load or fast load option through the library. Not all tape management systems, however, support the fast load option.

Setting Scratch Preferences

On scratch mount requests you can explicitly specify the media type you want to use, or you can have ACSLS select a media type.

In order for ACSLS to select a media type, you must pre-define a prioritized list of compatible media types for each drive type. This list is referred to as the “scratch preferences."

There is one set of preferences for the entire server; preferences are not defined by client.
If a compatible media type is not listed for a drive, the media will not be selected.

The following sections describe the user and system defined files that ACSLS uses in determining scratch preferences.

User-Defined Mixed-Media Files

The following are the user-defined mixed-media files that are located in $ACS_HOME/data/external/mixed_media/:

scratch_preferences.dat

User-defined preferences file. Primary source of preference definitions.
scratch_preferences.SAMPLE

Sample preferences file can be copied to create the scratch_preferences.dat file.

System-Defined Mixed-Media Files

Display the ACSLS mixed-media settings using drives_media.sh -f

Review the media compatibility settings saved in:

/tmp/media_compatibility.txt

This is the system-defined compatibility settings file. It is used only if the user-defined preferences file does not exist or is missing a drive type
/tmp/drive_types.txt

System defined list of supported drive types.
/tmp/media_types.txt

System defined list of supported media types.

How ACSLS Uses the Mixed-Media Files

The following table describes how ACSLS uses the mixed-media files to select a media type for a scratch mount request.

Table 7-2 How ACSLS Uses Mixed-Media Files

If the scratch_preferences.dat file ...	ACSLS does this...
Does not exist.	Uses the definitions from the system `media_compatibility file`
Lists more than one media type for a drive.	Selects the media types in the order listed.
Lists no media type for a particular drive.	Uses the data from the system `media_compatibility file`
Does not list a particular drive type.	Uses the data from the system `media_compatibility file`

Defining a Scratch Preferences File

Use this procedure to define a scratch_preferences.dat file, which contains an ordered list of scratch cartridge types to select for given drive types. ACSLS uses this file for mount * command where a media type is not explicitly specified.

The following example shows the contents of the scratch_preferences.SAMPLE.

Drive Type Name   Media Type Preference Name 
4480                   3480 
SD3                    DD3A 
SD3                    DD3B 
SD3                    DD3C

To define a scratch preferences file, do the following:

Log in as acsss.
Change to the external mixed media directory:

cd $ACS_HOME/data/external/mixed_media
Copy the sample scratch preferences file to create the user-defined file:

cp scratch_preferences.SAMPLE scratch_preferences.dat
Using a text editor such as vi, modify the list of preferences in the scratch_preferences.dat file:
- Follow the instructions in the comments at the top of the file.
- If you want to use more than one media type for a drive type, enter each media type on a separate line; the order of preference is from top to bottom.
Save the file.
From cmd_proc, restart ACSLS:

start