We're running a full Exadata 12c Rac. Tape guys complain about the number of jobs saying there's only one file per job. We backup to the flash recovery area and from there to tape. Even changing the filesperset parameter when going to tape doesn't change the number of files per job. Is there any way to get more than one file going per job?

I don't think it's a relevant forum for your questions, as NBU just provides a pipe for Oracle through the standard interface, as long as appropriate number of channels can be created - NBU has done its job and the rest is the responsibility of Oracle. Now because the interface is standard, you can replace NBU with BUE, NetWorker or God forbid, CommVault, you will still have the same issue if its root cause in RMANTo clarify again - NBU don't form backup sets and operate with Oracle logs and datafiles.

Check Max Jobs Per Client in Global Properties. Ensure this is more than 1. Value of 4 will allow 4 simultaneous jobs per client. Check MPX setting in Application schedule. Must be >1.Define more CHANNELs in rman script.One job per channel will be created. Filesperset will simply group more dbs into one backup job.

I appreciate the reply. We're opening up 12 channels, 2 per node. Are any of your suggestions going to increase the number of files instantiated per job? That's what's bothering the tape guys. They say it's taking more time because of the stopping/starting/searching/positioning...and the writing. If each job had as many files as I could put into them, then it could pretty much fly. As it is it's like in the old days when people set their block size too small so reading it was staccatto with lots of starts and stops. Tape guys want a stream of writes, not a bunch of starting and stopping.

RMAN has a parameter called FILESPERSET and it defines the number of files per backupset. What I would like to warn you about this setting - it really affects deduplication ratio if you're writing it to a deduplicated storage. Fixed block dedupe storages like NBU MSDP or Appliances will have the worst hit, variable block dedupe such as Data Domain will be impacted less but still dedupe rate will be considerably worse than with FILESPERSET=1.Now you really need to choose your poison...

Please tell us a bit more.How many media servers? How many tape drives per media server?How many simultaneous jobs generated by '12 channels, 2 per node'?What throughput is seen to each of the drives (Kbytes/sec)?What is the network speed between Oracle clients/nodes and media server(s)?'stopping/starting/searching/positioning' is a sign of slow throughput to the drives.So, yes, more simultaneous jobs per drive could help, but you need to do the maths to work out if there is sufficient bandwidth and media server resources.

RMAN Netbackup to tape - How to get more than one file per job

18 Replies

Marianne
Level 6
8 years ago
Check Max Jobs Per Client in Global Properties. Ensure this is more than 1. Value of 4 will allow 4 simultaneous jobs per client.

Check MPX setting in Application schedule. Must be >1.

Define more CHANNELs in rman script.
One job per channel will be created.
Filesperset will simply group more dbs into one backup job.
- safedba
  Level 3
  8 years ago
  I appreciate the reply. We're opening up 12 channels, 2 per node. Are any of your suggestions going to increase the number of files instantiated per job? That's what's bothering the tape guys. They say it's taking more time because of the stopping/starting/searching/positioning...and the writing. If each job had as many files as I could put into them, then it could pretty much fly. As it is it's like in the old days when people set their block size too small so reading it was staccatto with lots of starts and stops. Tape guys want a stream of writes, not a bunch of starting and stopping.
  - Mouse
    Moderator
    8 years ago
    RMAN has a parameter called FILESPERSET and it defines the number of files per backupset. What I would like to warn you about this setting - it really affects deduplication ratio if you're writing it to a deduplicated storage. Fixed block dedupe storages like NBU MSDP or Appliances will have the worst hit, variable block dedupe such as Data Domain will be impacted less but still dedupe rate will be considerably worse than with FILESPERSET=1.
    Now you really need to choose your poison...