We are running NetBackup 6.5.5 on Windows 2003 for our master and media servers. I want to change Multiplexing and multistreaming seetings on our media servers so that only one backup job goes to one tape head at a time. What combination of multiplexing and multistreaming would i need to change to accomplish that?

to be running at any one time then the only sure-fire way to ensure that only one job writes to a drive at any one time would be to amend it at the Storage Unit level. Reasoning: all things being equal (retention levels etc etc) if you have more than one policy/schedule to run & you have dropped all settings down to a minimum (multiple data streams, limit jobs per policy, media multiplexing), then the maximum number of jobs/streams potentially active would be one per policy. Therefore the number of active jobs writing to a tape here would be dependent upon the number of policies. The only way to ensure a one job/drive scenario would be to amend it at the STU level (un-tick Enable Multiplexing) - the common denominator.

How to configure NetBackup so a job only writes to one tape drive

J_H_Is_gone
Level 6
15 years ago
If you only want one job going to a tape at a time then take multiplexing down to 1.

Which means 1 job.

If it is at 2 then 2 jobs get to write to the tape at a time.

Your storage units have this setting

as well as your schedules in you policy.

But you can just change your policies and it should then go down to just 1 job at a time to each tape.
Andy_Welburn
Level 6
15 years ago
to be running at any one time then the only sure-fire way to ensure that only one job writes to a drive at any one time would be to amend it at the Storage Unit level.

Reasoning: all things being equal (retention levels etc etc) if you have more than one policy/schedule to run & you have dropped all settings down to a minimum (multiple data streams, limit jobs per policy, media multiplexing), then the maximum number of jobs/streams potentially active would be one per policy. Therefore the number of active jobs writing to a tape here would be dependent upon the number of policies.

The only way to ensure a one job/drive scenario would be to amend it at the STU level (un-tick Enable Multiplexing) - the common denominator.
marekkedzierski
Level 6
15 years ago
you can also create storage unit with only one drive.
cgoliver
Level 5
15 years ago
Set the multiplexing to 1 on the stu.
HEMANPR
Level 6
15 years ago
If you have some drives, You can also Set the policy to a expecific drive.

Do not use multiplexing or set to 1.
Will_Restore
Level 6
15 years ago
you could set Multiplexing to 1
Andy_Welburn
Level 6
15 years ago
Setting the multiplexing to 1 on the STU that is!

[[ will only go to 2 minimum]]
kproehl
Level 5
15 years ago
This is all very good information. Thanks for the replys.

We have 6 drives in our library and right now the multiplexing for all the polices is set to 6. Also at the storage level mutiplexing is checked and the number of steams per drive is set to 8. I assume I will need to change both of those to 1.

By doing this what could some of the conquences be?
marekkedzierski
Level 6
15 years ago
There will by only one stream per drive instead of 6 so your backup session will take longer and some jobs could miss backup window.
Andy_Welburn
Level 6
15 years ago
Depending on the size of your backup window, performance of resources, number size of backups etc etc it could mean that you don't have enough resources to complete all your jobs within the given period. Essentially you would be going from a maximum of 8 jobs per drive at any one time to only one job per drive.

You could drop it by increments & monitor? Depends what you want to realistically achieve at the end of the day.