Netbackup中volume ,media,image 数据库的作用

xiaomao2006

Details:

VERITAS NetBackup (tm) writes images to media and tracks the media and images in three databases that make up the NetBackup catalogs: the Volume database, Media database, and Image database.
These databases track the images and media and ensure that no images are overwritten, lost, etc. The images on a piece of media will not be overwritten while they are labeled as active un-expired images according to the databases. When a tape is full, the tape will not be used again until the last image written to that tape expires. That is, a full tape will not be written to until the last image on the tape expires. By default, NetBackup is configured to not mix retentions on a piece of media.  
Volume database
\veritas\volmgr\database\voldb
This holds the following information (Figure 1) for a piece of media.
Vmquery can  be used to view information about a particular piece of media.
Figure 1



Media database
\veritas\netbackup\db\media\mediadb
Media are added to this database as images are written to the tape.
There is a Media database located on each media server. This tracks media that the particular server has written to. Media can only belong to one Media database at a time. The media ID stays in the Media database until all images on the tape are expired.
Bpmedialist can be used to view information about a particular media in this database (Figure 2).
Figure 2



Image database
\veritas\netbackup\db\images
There will be sub-directories at this level for each client that is backed up. The client directories will contain ten-digit directories and files. The ten digits reflect the actual date/time of the backup. The Full file contains information about the backup. The .f (files file) contains binary information about the backup and a file/directory listing of all that was backed up (Figure 3).
Figure 3



Bpimmedia can be used to view information about a particular image (Figure 4).
Figure 4



The images on a media report can also give information about an image (Figure 5).
Figure 5



Catalog can also be used to view information about images (Figure 6).
Figure 6



Warning : The information in these three databases should never be manipulated manually. NetBackup will manage them and keep the databases consistent. Alteration of these databases in any manner other than that prescribed by NetBackup Technical Support can result in data loss. Great care should be taken when making updates to these databases through the available command line tools and they should never be manually edited through any other means.


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