append to a tape & not overwrite.

If the tape is ACTIVE (i.e. has space), is of the correct density, same retention, same Volume Pool etc etc for the backup that is running then it will append those images.

Hi
As Andy said data should be appended, but I would took backups on the different media on daily basis even if one media could satisfy all daily backups (Mon- Thu), becuase if this one piece of media would be damaged Your RPO will increase significantly. but it is up to You.

Thanks two. If  the tape is active(has space) , how to make  tape drive select this and append data ?

for all these daily backups. also consider setting this one option
"Keeping stand-alone drives in the ready state
To leave stand-alone drives in a ready condition after a backup or restore completes, use the nbemmcmdcommand to enable the -do_not_eject_standalone option. NetBackup does not eject the tape after an operation completes. The media is still ejected if EOM is reached or an error is encountered. Also, the media is ejected if the drive needs to be used with
another media or the media needs to be used with another drive. One standalone drive may be ready and contain suitable media. See the NetBackup Commands for UNIX and Linux for detailed information on the nbemmcmd command."

This was taken from NBU admin guide for unix vol2

What's nbemmcmd  command? I am not understanging this.

Hi Chong

nbcemmcmd command is in Netbackup 6.x

Hi Chong

nbcemmcmd command is in Netbackup 6.x

My version is 5.0 MP7. How can I append media  on a daily basis?

For NetBackup 4.5 and 5.x systems, there are two different ways to configure NetBackup so it will leave a tape in a standalone drive once a backup completes. This can be done via the NO_STANDALONE_UNLOAD touch file, or the DO_NOT_EJECT_STANDALONE entry in the vm.conf file. It is only necessary to choose one of these options in order to prevent the ejection of tapes from a standalone drive after a backup completes.

http://seer.entsupport.symantec.com/docs/199100.htm

Thanks. I have NO_STANDALONE_UNLOAD file and to prevent the ejection of tapes.But I need to know that, if a tape is active and has space, how can I append data(not overwrite) on it on the next day?

i.e. "NetBackup will always append to a tape & not overwrite"

and

"If the tape is ACTIVE (i.e. has space), is of the correct density, same retention, same Volume Pool etc etc for the backup that is running then it will append those images."

Tapes does not get overwritten unless within the catalog, the data is passed the age of retention.

If have a tape that is A00000, and it's active and selected for backup, NBU will read the database and position to the last filemark and append backup there until EOM (end of media).  Then this tape is considered FULL.  Full tapes do not get considered for backups until the last data it holds is expired.  If the backup was not completed when it hit EOM, it will request for a NEW/Expired tape.  You may not use another ACTIVE tape in situation where backups has to span more than 1 tape.

To be clear, if you START a new backup, the first tape NBU will request would always be an available ACTIVE tape.  Should that job needs to span to another, the follow tapes must be scratch tapes.

NOW if you have a second master server, and you stick this tape into that master server, it's catalog has no records of this tape, therefore the data WILL overwrite it.

I tried an active tape to continuous backup, but can't , and staus became frozen, the error as follows,

Error bptm (pid=14229) FREEZING media id A00000, the allocated date does not match the volume database assigned dat - possible database inconsistency

This tape  is the same pool and retention level  with the policy.

hi, guys :

   Repeated write failures are usually the cause for setting a volume to the FROZEN state or a device to DOWN. A volume is also set to FROZEN if the write failure makes future attempts at tape positioning unreliable. Common reasons for write failures are dirty write heads or old media.

The following are the default values for the error thresholds:
■
The media error threshold is 2 (that is, NetBackup freezes media on the third media error in 12 hours).
■
The drive error threshold is 2 (that is, NetBackup downs a drive on the third drive error in 12 hours).
■
The time window for errors is 12 hours. You can use the NetBackup nbemmcmd command with the -media_error_threshold, -drive_error_threshold, and
-time_window options to change the default values. For more information about nbemmcmd, see NetBackup Commands for UNIX and Linux.
To reverse a freeze action
◆ Use the bpmediacommand to unfreeze the volume.
To reverse a down action
◆ Use the NetBackup Device Monitor to set the device to Up.

I think my media may be wrong assigned date for backup. This is a previous backup tape with the same retention level. How can I check the active media is suit for next backup?

Thanks. It's OK now.