NDMP Compression

[tvmo]

Hello,

I know that NDMP does support compression however I don't get an option to select it within my Netbackup 6.5 policy. Why is this?

Thanks

[Andy_Welburn]

Come across the following post, but no supporting evidence as yet (maybe RahulG could comment?):

Software Compression and Software Encryption does not work for NDMP based backups of Filers.

https://www-secure.symantec.com/connect/blogs/software-compression-and-software-encryption-does-not-work-ndmp-based-backups-filers

Time for Google!

[tvmo]

Thanks Andy, I saw that I just didn't understand it.

Is the post saying that you have to rely on hardware compression rather than through NetBackup?

[Andy_Welburn]

Certainly not available in the GUI as you know. May be able to use the command line but as Rahul states job may finish but no compression evident.

Would be nice to see some supporting documentation "This is by design and not a problem".

Maybe that at the software level NB is not capable of compressing the NDMP data stream .... not sure, it's probably waaay over my head!

[AAlmroth]

I think the NDMP standard is a bit limited in a lot of areas, but then again it is a standard, and all parties must agree to a level of conformity that all parties can see justifiable. Hence, a lot of nice features are left out.

Anyhow, compression has history really not been a problem with tape technologies supporting it and giving optimally 2:1 compression, and I could really only see NBU "native" compression usable in remote NDMP, where the data passes the media server.

With the new NDMP PureDisk streamer (currently only for NetApp I believe) can achieve a very good compression (de-dup + ZLIB or LZO compression) when using remote NDMP over the LAN. downside is still that all the data must move over the LAN...

The downside with NDMP is that the data stream is not standardized, only the management data, thus no generic handling of the stream format, leading to vendor specific implementations. Maybe NDMP v123? ;)

/A

[dunno]

So can you compress at the NDMP client using NBU prior to traversing the NDMP backup across the network?

What about compression when writing to tape? Can you do this in NBU?