02-17-2021 05:28 AM
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
Solved! Go to Solution.
02-18-2021 03:50 AM
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.
02-17-2021 06:01 AM
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 ;)
02-18-2021 03:40 AM
f the tape is full, does netbackup stop recording data or does it write new data and delete old data?
02-18-2021 03:50 AM
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.
02-18-2021 04:07 AM - edited 02-18-2021 04:08 AM
Thanks for the response.
02-18-2021 06:59 AM - edited 02-18-2021 07:00 AM
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 :)
02-18-2021 09:14 AM
Hello @Nicolai
Thank you for the response.