NDMP NAS Backups + TIR

[Shaun_Taylor]

We are backing up NAS file systems on EMC Celerras to Data Domains using 3-way NDMP over a 10Gb network. Looking at our NDMP backup policies, the option to enable TIR is greyed out. Is this because NetBackup NDMP policies do not support TIR, or because it is automatically enabled and cannot be turned off?

[Yasuhisa_Ishika]

TIR is not supported in NDMP backups as such functionality is not defined in NDMP specifications. TIR is NetBackup's feature that can work with NetBackup clients in file backups.

[Shaun_Taylor]

Thanks for clarifying this so quickly Yasuhisa - much appreciated.

[bills]

Yasuhisa, are you sure that NDMP backups don't collect TIR data?  I don't see anything in the admin guide or the NDMP guide saying either way, but I do see some references to it in several forums.  In addition, I had a nasty support issue with NDMP backups  where the TIR data was failing to be written out.

Bill

[Yasuhisa_Ishika]

Bills,

As I wrote above, NDMP specification does not include such functionality. Why do you think TIR is supported in NDMP backups although "Collect true image restore information" is unchecked and greyed out?

As per NetBackup DataCenter 4.5 Administrator's Guide,  TIR is supported only in certain policy type. If greyed out without check, this means TIR is not supported in this policy tupe.

[Yasuhisa_Ishika]

NetBackup DataCenter 4.5 Administrator's Guide is here.

http://www.symantec.com/docs/TECH19739

[bills]

Yasuhisa:

I agree that having an option unchecked and greyed out is a good indication that that option is not available - however, as I said, I spent the better part of 6 months troubleshooting NDMP backup failures with NetApp and Symantec where the NetBackup logs made it clear that it was failing to write TIR data.  TECH13813 seems to suggest that NDMP collects TIR data as well: http://www.symantec.com/business/support/index?page=content&id=TECH135813

Bill

[Yasuhisa_Ishika]

I'll test NDMP restore to confirm if NDMP restore works as TIR. I have to prepare test environment, so please give me days to reply.

[Yasuhisa_Ishika · Accepted solution]

I tried to restore from NDMP full & incrementals with NetApp. As a result, NDMP restore does not work like TIR.
I could not browse NDMP backups with  "True Image Backups" restore type, and with Normal Backups restore type I could browse backups but restore worked as normal backups. Removed files were restored.

Whereas, in bpimagelist output, NDMP backup images has TIR fragment. I'm not sure why it was generated(maybe some internal use), but as above, I confirmed that NDMP backups does not support TIR.

[bills]

That is excellent information, Yasuhisa - thanks for taking the time to test it out.  We never consciously used TIR with our NDMP backups, but it was that TIR fragment seen in bpimagelist that was failing - thus I assumed that the backups were collecting TIR info.  Curious to know what it's really doing with those....

Bill

[smurphy]

bills and all:  The bptm logs always refer to 'TIR' processing at the end of the backup.  Even though it's not applicable to NDMP, bptm does not know any better.

Typically, in an NDMP context, 'TIR' refers to the inode metadata streaming and verification that occurs when the actual physical backup is completed.

Understandably confusing.

[watsons]

Interesting one!

First look at it, I would say TIR is not a part of NDMP backup.

But the bug report that bills pointed out had me pondering for a while... the technote however did not clearly specify the exact environment.

I guess when we say "NDMP backup", we generally mean the policy is of "NDMP" type. And with that, TIR is definitely not supported because in the background work, the backup command is carried out by the NDMP host, not Netbackup. Netbackup has no control at all to enable TIR as it requires a tracking folder in the client side.

However, you can have a NDMP data backup via "Standard" or "Windows" type by exporting it thru NFS/CIFS. In that case, yes you can enable TIR in your policy but how accurate the TIR can follow on the data changes, will be a question. Had not tested this before, but certainly there has been discussions on this somewhere.

[Shaun_Taylor]

Thanks for all the information everyone - an excellent example of why I come here with my questions!