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is considered full when the disk is full

Tabriz
Level 5

Hi,

there is LTO 6 tape  in netbackup .4.5 TB data writen to the tape.But media status show full? LTO 6 tape is 6.25 TB compressed.

What can be reason?

Thanks

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Accepted Solutions

Marianne
Moderator
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@Tabriz 

When a tape is full, NetBackup will not write anymore backups to it.
NetBackup will look for a new tape to write backups.

The Full tape will keep this status until ALL images (backups) on this tape have expired. The expiration date is determined by the Retention Period that is selected in the Policy Schedules.
The tape will then be 'unassigned' and become available (go into Scratch).
Only at this point can the tape be overwritten from the start.

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6 REPLIES 6

quebek
Moderator
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Hey

Your data which is not not compressing 1:2.5 and that's all.

So whenever I am sizing tape drives I do never take into account tape/library capacity based on assumed compression - always native. By doing so I am on safe side ;)

f the tape is full, does netbackup stop recording data or does it write new data and delete old data?

Marianne
Moderator
Moderator
Partner    VIP    Accredited Certified

@Tabriz 

When a tape is full, NetBackup will not write anymore backups to it.
NetBackup will look for a new tape to write backups.

The Full tape will keep this status until ALL images (backups) on this tape have expired. The expiration date is determined by the Retention Period that is selected in the Policy Schedules.
The tape will then be 'unassigned' and become available (go into Scratch).
Only at this point can the tape be overwritten from the start.

@Marianne 

Thanks for the response.

Nicolai
Moderator
Moderator
Partner    VIP   

Hello @Tabriz 

Netbackup don't know a tape capacity, it keeps writing until the tape drive sends the EOM (End of medium) signal to Netbackup, and then a tape exchange is initiated. 

Another source to "lost capacity" is tape drive shoe shining, e.g not streaming the drive at it minimum rate. Every time a tape drive stop to wait for more data, a inter block gab is written to tape, add enough of them and you wont reach the tape capacity. 

As mentioned, always count in native tape capacity, compression gain is considered a gift for the backup admin :)

 

Hello @Nicolai 

Thank you for the response.