How long a tape is Active??

[OHWS]

What determines how long a tape can stay active?? I visited the Veritas support site and read about how the library chooses a tape but I did not see any info regarding the default setting for how long a tape will stay active after the first write. I'm assuming it is 24 hours by default for all tapes except LongTerm retention. I was thinking of changing this to 48 hours to better utilize my tapes. Have any of you changed this option for better or worse? Thanks!

 

[Stumpr]

NetBackup keeps a tape active until it becomes FULL, SUSPENDED, or FROZEN.

Bob Stump
Incorrigible punster -- Do not incorrige

 

[PGPhantom]

The active status of a tape is determined byt he retention levels of backups on those tapes. One of our retention levels is 7 years so the tapes will stay active for 7 years.

 

[OHWS]

From what I have read the robot will go for tapes that are loaded in a drives first with the appropriate pool,retention,etc.. and if it finds a tape that matches it will use this first. After that it goes to the library and find media that meets the previous criteria with the least amount of mounts. I could have a tape that get written to today and if it has 50 mounts and tomorrow I have tapes become available with 20 mounts it will use those tapes first. So it could be until those tapes fill up that I get to use the 50 mount tape again. Making the expiration date really after the last image was written(+retention). Please correct me if I'm wrong about this. I have been looking into changing the unmount time to something other than the default 180 seconds to try and encourage filling up tapes soon after the first write. Thanks for your responses!!

 

[Stumpr]

Your understanding about tape selection is correct.

However, please remember that the use of the unmount delay is only for user directed backups. From the Admin Guide:

When MEDIA_UNMOUNT_DELAY is specified, the media unload is delayed for the specified number of seconds after the requested operation has completed. (Applies only to user
operations.)
For example, assume the delay is 120 seconds:
MEDIA_UNMOUNT_DELAY = 120
Use this option by adding it to the /usr/openv/netbackup/bp.conf file on NetBackup servers or enter a value for Media Unmount Delay in the Media host
properties. (See “Media Unmount Delay” on page 280.)

If anyone knows with certainity (i.e. you tested it) of another way to keep the media loaded during a normal sceduled backup then please enlighten this forum.

Bob Stump
Incorrigible punster -- Do not incorrige

 

[OHWS]

Well it looks like I won't be changing that value any time soon since I do not use any of the DB extension clients and do not have any user backups except (archives). Thanks for your help again!!

 

[goace]

Anyone know how to reset the amount of Volume Mounts from say 50 back down to 0? I have data on the volume already, but need to keep it and just append to it until the tape is full then archive it long term. Thanks!

 

[lenski]

The standard process is for tapes to be appended too. If you have data on a tape it will not be overwritten untill the image expires.

 

[goace]

Right-exactly why I pose my question. According to Veritas, how the volume mgr picks what media to use next is if there are two available tapes with everything being equal-except mount count, Netbackup will mount the tape with the lesser number of mounts. Since we continually add new media, the older tapes are never being written to nor vaulted. Thanks for your response.

 

[Stumpr]

use the command
/usr/openv/volmgr/bin/vmchange

(Change volume's number of mounts count / cleanings)
vmchange [-h <volume_database_host>]
-n <num_mounts/cleanings> -m <media_id>

example
vmchange -h master1 -n 0 -m 123456

This works in windows too.
just change the path to reflect your installation

Bob Stump
Incorrigible punster -- Do not incorrige