NDMP - how does it work? (file level or block level)

[gkman]

Hi

theoretical question here-

I always thought that NDMP was a communication protocol in the basic form of: backup server request files in X path for backup and NDMP host passing these files. in case of a incremental backup request the NDMP host sends only files that have changed since the last backup (file level backup only- meaning the NDMP host itself does the inventory check \ block level comparison etc- but in the end result sends the entire file to the backup server)

I am now told that NDMP does enable in fact real block level backups.

I wasn't able to find anywhere a conclusive answer to how NDMP works (if it's a block-level backup or file-level backup)

can anyone help please? (I would like an official document of some sort of backup or storage vendor if possible)

thanks in advance for the help.

[Marianne]

Are you referring to Accelerator for NDMP? 
Where file-level backups are done to supported deduplication storage that deduplicates at block-level?

Herewith some info about Accelerator:

https://www.veritas.com/content/support/en_US/doc/18716246-126559472-0/v64001338-126559472

And Accelerator for NDMP:

https://www.veritas.com/content/support/en_US/doc/24427212-127304472-0/v99897177-127304472

[gkman]

Hi Marianne.

I didn't understand your reply (specifically your question)

I am "going back to basics" on NDMP protocol itself (as I have obviously missed a few lessons.) regardless of the different techniques used by Netbackup to speed up the process. 

I know about how the protocol work communication wise (the host, client and controller)
but I never learned about the types of ndmp backups.

from the second link you have sent I read "Accelerator for NDMP supports only the DUMP format"
what other formats are there? are they block level or file level?
up until now I thought that ndmp was just like copying files over the network with smb (from the data passed (file level) point of view)

thanks again for the help

[Marianne · Accepted solution]

The answer to your questions are actually outside of NetBackup (or any other backup software with NDMP agent).

In short - NDMP does file-level backup.
Most common backup types are tar and dump.

A bit of NDMP background :
http://searchdatabackup.techtarget.com/feature/Common-NAS-backup-challenges#q2

Hope this helps.

[gkman]

thank you very much.

it is exactly what I was looking for.