Forum Discussion

H_Sharma's avatar
H_Sharma
Level 6
10 years ago

Media Multiplexing

Hi Experts, Previoulsy I had many jobs in queued state and these got failed with 196 errors. We have 8 drives and Media Multiplexing was set to 1 in full and differential backups in policy sche...
7.6
Backing Up
Backup and Recovery
BETA
NetBackup
Windows Server (2003-2008)
  • Marianne's avatar
    Marianne
    10 years ago

    Yes. 1 drive can write 3-4 backup jobs in the same tape at the same time. 
    Perfectly fine.
    By writing 3-4 (slow) backups simultaneously to the drive (multiplexing) you keep the drive streaming with the increased throughput.

    My experience over 15 years has been that MPX of 4 gives good backup as well as good restore performance.
    You need to perform your own test restores from multiplexed backups to see if restore performance is acceptable.

    Have you had a look at the section in Admin Guide (link in my previous post)? 
    It explains nicely what happens during multiplexing and multistreaming with pictures that makes it easy to understand.

     

    The same info can be found in these TNs: 
    http://www.symantec.com/docs/HOWTO86804 
    http://www.symantec.com/docs/HOWTO86888 

jim_dalton's avatar
jim_dalton
Level 6
10 years ago

Agree with bmitche: backups you have to do day in day out : thats where you want the performance, restores you dont do nearly so often <1% of the backup. For big data and high throughput I use low MPX or zero eg SAP and ORA dbs directly attached to tape, for bog standard clients and OS full backups I go for 3, for incrementals of same I go for 10.  But as Riaan says, if you're maxing the drive in any case you're gaining nothing but this is rare.

Jim