If you come across Backup Exec GUI. If you select Tools--- Options---Media Management. If you see Media Label Configuration. You will see that Media type will have a label marked with Prefix and Digits. So for example if you have an autoloader with 10 slots and if the media is a 4mm tape, then the prefix would be 4M, followed by 000001. The next media label generated for an unlabeled 4mm tape would be 4M000002, and so on.
As an additional reference, kindly refer our Administrative Guide for Backup Exec v9.1
VERITAS Backup Exec (tm) 9.1 for Windows Servers Administrator's Guide (English)
http://seer.support.veritas.com/docs/266190.htm
(Please refer page number 202- Media Labeling )
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To start with, please refer the technote mentioned below:-
Title:- How to partition a loader and still be able to target a specific drive to be used for a backup operation.
http://seer.support.veritas.com/docs/241773.htm
Also please read the following explanation, this would help you better understand the problem.
Backup Exec picks media from autoloader's slot according to Allocation date of media.
Following Example shows how media is picked in sequence:
Suppose Setup used is : 6 slots autoloader, one partition created using first 3 slots.
Please follow the steps mentioned below for Backup Exec to take media from Autoloader's partition in a sequence:
1.Please make sure that the Media Overwrite Protection Level is set to "Full" or "Partial" from Tools > Options > Media Overwrite 2. Please make sure that the "Overwrite scratch media before overwriting recyclable media contained in the targeted media set" is selected, from Tools > Options > Media Overwrite 3. Move all media to scratch media and then erase them in sequence i.e. Media from slot 1 should be erased first, then Media from slot 2 and then slot 3.
Erasing all the media in sequence would change Allocation date (or time) in sequence (media from slot 1 will have lower Allocation time then of media 2 and 3). Click on Autoloader partition from the Devices tab, on the right hand side it will show each media's Allocation time Whenever an Overwrite backup will run (select Append to media, Overwrite if no Appendable media found), it would take media from slot 1 for overwrite.
After the first job finishes, whenever any Append job will run (Append to media, Overwrite if no Appendable media found), media 1 will get append. When the media 1 capacity reaches its limit, media from slot 2 (media 2) will be used for overwrite operation.
Please note that if the job is selected for Overwrite only and the property of the media set is having no overwrite protection period (or the overwrite protection period expired), next available media from scratch media (having lower Allocation time, media 2 from slot 2) will be used for the job, as "Overwrite scratch media before overwriting recyclable media contained in the targeted media set" is selected.
If the requirement is for picking up tape from slot 3 first, simply change the system date to a day before than that of two media of the two slots and run erase on slot 3. This would change the allocation date of the media 3 to a day less than the two media (1 and 2). After erase change the system date back to normal and run backup job. This would take tape from slot 3.
Important:
Allocation date will be changed by Overwrite or erase job on the tape. Thus it is not always required to erase the tapes for backup to take tapes in sequence i.e. suppose in above case all 3 media are overwritten in sequence, their Allocation date will be in sequence. Whenever these tapes need to be reuse, simply put these tapes in sequence in the Autoloaderâs slot i.e. media 1 (which was in slot 1 earlier) should be placed in slot 1 and so on and move the media to scratch.
Whenever a tape from a user defined media set will be erased, it will be moved to scratch automatically and if the backup job is selected as âAppend to media, Overwrite if no Appendable media foundâ and if the user media set contains some more tapes in it, these tapes would be used for backup (append). When overwrite job is selected, tape from scratch would be used as "Overwrite scratch media before overwriting recyclable media contained in the targeted media set" is selected, from Tools > Options > Media Overwrite.
You can refer the following TechNote:
1. An explanation of the "Overwrite Protection Period" and the "Append Period".
http://seer.support.veritas.com/docs/237374.htm
We hope this helps.