Optimized Duplication - How to switch it off ?

[TempoVisitor]

Hi, can you help ?

Using NBU 7.1.0.2 and OpenStorage we have a strange behavior :
Backup done on Dedupe DiskPool : OK (verify and restore OK)
Backup done on Tape : OK (verify and restore OK)
Duplication from Tape to Dedupe Disk Pool : OK (verify and restore from copy 2 : OK - report images on media = same nbfiles and size)
Duplication from Dedupe Disk Pool to Dedupe Disk Pool :OK (verify, restore, report on images : OKOKOK). Strange behavior during the duplication, it announces it will do an optimized duplication, as both source and dstination are deduped, and connected. I didnt have to configure anything.

Problem is :
Duplication from Dedupe Disk Pool to Tape : by bpduplicate, or console, or Vault, or SLP => Job says it's ok BUT :
- restore rom copy 2 fails
- verify from copy 2 fails : says there is more files in the database that on the image to verify
- and indeed : report on images show that the amont of data present on original copy 1 is much larger in kb than copy 2 !!!

Intuition
NetBackup tries to read the data from Deduped DiskPool as if it wanted to use optimized duplication, but the destination cant manage this small flow of data.

Question
Is it possible to completely prevent Optimized duplication by bpsetconfig or in the bp.conf ?

FYI
The openstorage solution is FalconStor - there is a ticket open with both FalconStor and Symantec, but they don't feel comfortable with that specific case.
It looks like using OST should always be done to duplicate optimized, and not toward a Tape !!!

I don't have any other location to test the duplication, from OST to Basic Disk, for example.

[Kiran_Bandi · Accepted solution]

You have problem when restoring data from tape, which have duplicated data from dedup disk pool. While duplicating data between dedup disk pool to tape, NBU won't do optimized duplication. Duplication between deduped disk pools will be optimized and will be much efficient than normal duplication. I do not see any advantage in disabling it.

But if you want to do so, select storage unit group as destination instead of selecting storage unit. Then NBU will not do optimized duplication. But again no advantage with this.

Coming to duplicating data from dedup disk pool to tape, data will be rehydrated while writing data to tape. (means will be written in original form, not deduped data anymore). That is why you can see a difference in sizes.

[TempoVisitor]

Thanks for this workaround. I like the idea of STU Group to prevent opt dedupe.

BTW, the error may come from the buffer size, different between disk and tape.

What I don't understand yet is why duplication works from Tape to OST_DP, but not frm OST_DP to Tape.