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felonious_caper's avatar
felonious_caper
Level 5
13 years ago
Solved

Multiplexing

Just a quick question about multiplexing.

In the master host I have 2 jobs per client

In the policy I have 2 jobs per policy

The schedule is set to multiplex 2

The storage device is set to multiplex 2

 

Now... In the policy, multiple data streams is OFF.

 

All of my policies share this set up. Will netbackup send multiple data streams(from different policies)  to one storage device using this configuration?

 

Do multiplexing and multiple data streams have to be used together?

 

Is there an advantage to using multiplexing without multiple data streams?

Backing Up
Backup and Recovery
NetBackup
  • Mark_Solutions's avatar
    Mark_Solutions
    13 years ago

    In addition to the excellent advice you have been givenm so far, to answer you specific questions ...

    Q. Will netbackup send multiple data streams(from different policies)  to one storage device using this configuration?

    A. Yes - based on your config it can send two streams to each tape device - provided that they are using the same retention period for the backup (by default). This can be for 2 clients in one policy or 2 clients from 2 different policies

    Q. Do multiplexing and multiple data streams have to be used together?

    A. No - you do not need to enable multiple data streams - this just affects the number of jobs that would run for each client, not how it is written to tape - it is a different principle.

    Q. Is there an advantage to using multiplexing without multiple data streams?

    A. This all depends on how many clients, policies and tape drives you have and the throughput of each client. Usually multiple data streams are used for slower clients to get more total throughput.

    I have found that 4 to 6 is a good figure to use for multiplexing as tape drives are fast at block location these days so this has little or no effect on restores.

    Finally for now bear in mind that if you are using disk as your backup target the multiplexing in the schedules has no effect and the only limiter is the number of streams set on the disk storage unit.

    Hope this helps

  • Omar_Villa's avatar
    Omar_Villa
    Level 6
    13 years ago
    Any policy or sched u select that uses the stu will run all jobs with stu mpx setting and dont matter if r multistreaming
  • Marianne's avatar
    Marianne
    Level 6
    13 years ago

    Have a look at this excellent explanation and sample diagram in NBU Admin Guide for UNIX and Linux, Volume I  http://www.symantec.com/docs/DOC3650 on p. 657 under the title Example of using multiplexing with schedules

  • Mark_Solutions's avatar
    Mark_Solutions
    Level 6
    13 years ago

    In addition to the excellent advice you have been givenm so far, to answer you specific questions ...

    Q. Will netbackup send multiple data streams(from different policies)  to one storage device using this configuration?

    A. Yes - based on your config it can send two streams to each tape device - provided that they are using the same retention period for the backup (by default). This can be for 2 clients in one policy or 2 clients from 2 different policies

    Q. Do multiplexing and multiple data streams have to be used together?

    A. No - you do not need to enable multiple data streams - this just affects the number of jobs that would run for each client, not how it is written to tape - it is a different principle.

    Q. Is there an advantage to using multiplexing without multiple data streams?

    A. This all depends on how many clients, policies and tape drives you have and the throughput of each client. Usually multiple data streams are used for slower clients to get more total throughput.

    I have found that 4 to 6 is a good figure to use for multiplexing as tape drives are fast at block location these days so this has little or no effect on restores.

    Finally for now bear in mind that if you are using disk as your backup target the multiplexing in the schedules has no effect and the only limiter is the number of streams set on the disk storage unit.

    Hope this helps