We all backup TBs and TBs of data all day through fiber and through LAN.. either on disk,VTL or on tape
may time we find over selves in trouble when we are asked about Restore specially if its a crucial business requirement from top ones.. if tape is having i/o error or something else.. there is no one to blame but still have to find out answer.. I just want to know if any one of you is aware if there is checksum kind of feature available
in nbu where we can feel safe in what ever we are backing up.. which will check restorability of data in future
NetBackup can verify the contents of a backup by reading the volume and comparing its contents to what is recorded in the NetBackup catalog.This operation does not compare the data on the volume to the contents of the client disk. However, the operation does read each block in the image to verify that the volume is readable. (However, data corruption within a block could be possible.)
But the only way to be 100% sure would be to do a test restore - not many of us have the resources to accomplish this tho'!
As Andy has already mentioned, there is no better way to be 100% sure about a backup without doing a restore.
You can read the tape contents by using bpmedialist -mcontents command or through GUI
Media Contents Report
The Media Contents report lists the contents of media as read directly from the media. It lists the backup IDs that are on a single media ID. It does not list each individual file. This report does not apply to disk storage units. Note that the storage unit may stay in use for some time after the break if the following occurs: you attempt to abort the command by entering ctl-c and the requested media are not mounted or positioned. Each entry in the report appears as that area of the storage unit is read.
The -l format for the Media Contents report produces one line for each backup ID and contains the following fields. For more detail, see the Media Contents Report section in the NetBackup Administrator’s Guide. Any of the following fields that are not documented in that section are reserved for NetBackup internal use.
■ version (1 denotes a DB backup image, 2 denotes a regular backup image)
■ backup id
■ creation time
■ expiration time
■ retention level
■ fragment number
■ file number
■ block size (in bytes)
■ client_type *
■ copy_num *
■ sched_type *
■ flags *
■ policy name *
■ schedule label *
* These fields are significant only if version is 2.
Or you can configure an inline copy for a critical or on-demand backup, which will create multiple copy at the same using one read from client.