Tape Media - Wasted

[systematic92]

We have the following:

BEXEC 2014
2 Tape Libraries (4 drives in one library and 3 drives in the other)
Several NDMP backups
Mon-Thurs Incrementals
Fri-Sun Fulls

The problem is the space being used on the media and having to reorder more and more LT05s

On the incremental days, there are 10-12 tapes being used. Before pulling these tapes out, we notice that the majority of them have like 90% of the tape unused.

The incrementals go off-site for a period of 4 weeks (OPP) and then come back to us to repeat the cycle.

Is there any way we can use the exact or close to exact number of media without tape space being wasted?

One waywould be to simply place the x number of LT05s into the libraries each night as opposed to loading both libraries with 50 LT05 tapes (normal habit). Is there a way that something can be configured in BEXEC to fill up the tapes in use befor emoving onto a fresh one.

APP periods are set to 24 hours so there is more than enough time for the tapes to be appended to. Typicall all our Mon-Thurs jobs take about 12 hours to complete (all of them).

Thanks 

[CraigV]

...does your first job write/overwrite the media, and are the rest configured to append to the media?

Thanks!

[pkh]

You have previously asked a similar question. https://www-secure.symantec.com/connect/forums/too-many-tapes-being-used-ndmp-incrementals Don't you understand the solution? I would suggest that you read the tape management chapter in the Admin Guide

[Colin_Weaver]

As you have multiple tape drives, if you are running backup jobs in parallel they will use different tapes, as such when you say "Several NDMP backups", you may need to try and merge into less individual backup jobs so that the resources are backed up one after the other (or serially) . Failing that you will need to adjust start times of the jobs manually so that they do not run in parallel (except where you want them to and then use different media sets and / or target tape drives for breaking out the parallels)

Note 1: this is in addition to making sure the start as append is used and that the media sets are also correctly defined (any jobs you want to use the same tapes MUST use the same media set)

Note 2: if you want multi-plex multiple parallel jobs onto a single tape storage device then Backup Exec is not the correct product, NetBackup has facilities to both Multi-Plex (multiple jobs parallel jobs to one storage device) and multi-stream (one job to multiple tape devices in parallel) You would need to check that this facility is available during NDMP backups however if looking into NetBackup.

[systematic92]

Cheers Colin.

That is the issue.

We have say 12 jobs run in one evening. For arguments sake, lets say the jobs are named Job 1, Job 2, Job 3 - 12......

7 will immediately be taken (we have 7 drives in total)

Job 1 only needs to use 10% of the storage available.

What happens to the media that is being used by Job 1 when it finishes? Does it get released back to the library and get chosen for another job later down the line?

What tape will get used for Job 8? WIll the tape that was used for Job 1 (90% free) be pulled from the library?

Thanks,

[Larry_Fine]

Some suggestions:

1) Start only your 7 (since you have 7 tape drives) preferred/longest jobs at the opening of your backup window (say 10 pm).  Then schedule your remaining 11 jobs to start 5 minutes later (10:05 PM).  That lets the jobs that will be queued (waiting on an available tape drive) a chance to properly analyze the drives and appendable media available.  When you shotgun start all 18 jobs at once, each job looks to see if there is appendable media available at that instant, decides that there isn't any and then goes looking for overwritable media.  Once a job switches to looking for overwritable media, I don't think it will ever re-evaluate the situation and look for appendable media.

2) Investigate extending the "Next Job Wait Time" to keep the tapes that are finished with one job in the tape drive longer, which gives the next job time to re-use that same tape easier.  see https://www-secure.symantec.com/connect/forums/backupexec-2012-disable-auto-eject-tape-library

[Colin_Weaver]

If Job 1 finishes, if Job 8 is queued to start AND is set to use the same media set AND is set to one of the Append at start options then it should use the same tape as Job 1 (although if there is another appendable tape in the same media set it might choose the other tape first.)

If however Job 8 is set to overwrite at the start then it will usually use a completely different tape (this assumes that tape from job 1 is overwrite protected)

If Job 8 is set to use a different media set from Job 1, it will look for an appendable media in its own media set so ignore the tape used by Job 1 and then if it cannot find Appendable media in its own media set it will start looking for overwritable media (and for that specific instance of that job not switch back to looking for appendable)

if however Job 8 and Job 9 are both queued to start then which one actually starts will of course affect what Job 8 does (and then which media sets Jobs 2 to 7 were using and when they finish also affects things)

As you can see your settings massively affect the behaviour (as does the order in which the first jobs finish and starting the jobs in parallel if you actually want them to be on the least number of tapes.)

[Colin_Weaver]

Just a comment as I am not sure of the behaviour (and can't test it) but it is possible that because the NDMP device controls the robotic movement that Backup Exec Next Job Wait Time Setting may have no effect when NDMP Option backups are running.  (Point 2 of Larry's info)