Incremental Restore with Replication

Backup Archive and Restore (BAR)
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A1
Visitor

Incremental Restore with Replication

We are currently on TD v16.10 (no data mover) and want to restore few databases from one TD System to another (different locations). We generally do a full backup, replicate and restore using DSA.

Is there a way to do the replication and incremental restore if we do a Delta or Cumulative Backup on the Main system ?

10 REPLIES
Teradata Employee

Re: Incremental Restore with Replication

At least in 16.20 and earlier, a DSA restore operation always includes restoring a Full backup, and optionally one Cumulative and/or multiple Deltas. You can't do an incremental restore on its own. You might potentially be able to replicate Full backups less often, but the restores would take longer.

A2
Fan

Re: Incremental Restore with Replication

I understand the concept of Delta and Cumulative backup and Restore. The key question which I would like to understand is about how will these work with Replication across Data Centers basically replication to a different Data Domain. 

Highlighted
Teradata Employee

Re: Incremental Restore with Replication

Replication of the save set image itself and the related metadata necessary for a restore would be essentially the same, whether the backup type for a particular run of the job is full or incremental.

 

Enthusiast

Re: Incremental Restore with Replication

Your storage team will have to setup a DD boost setup to accomodate DD replication between data centers. I think DD boost is a cost feature in BAR. 

A2
Fan

Re: Incremental Restore with Replication

I think the question is not clear enough. We already have replication setup and do it for a FULL Backup and Restore without any issues. 

The scenario I'm looking for is:

  1. Setup a Delta Backup. Full on Sundays and Delta for rest of the week.
  2. Full Backup runs on Sunday from System A in one Data Center, replicate (data & Metadata) and Restore in System B.
  3. Delta Backup runs on Monday and gets replicated onto the other Data Center.

WIll the Backup system (DSA, NetBackup, etc ) know that this delta which got replicated on Monday is supposed to be linked to the FULL back from Sunday while restoring on System B? 

And will this scenario work also for Cumulative backups as well ? 

 

Teradata Employee

Re: Incremental Restore with Replication

That "link" is included in the metadata that needs to be replicated.

 

Note that if you ask to "restore the Saturday delta" (on System B), currently that operation would restore the Sunday Full followed by six Deltas.

Enthusiast

Re: Incremental Restore with Replication

Yes, When you pick the date when you took the delta on syatem A and try to restore to that day in system B it should do the full restore and  Delta on the restore to system B. The same applies to cumulatives as well. I got to know from 16.20 and above BAR has the capability of doing delta restores as well without doing the full restores. 

A2
Fan

Re: Incremental Restore with Replication

Thanks Fred and Abhi for your comments.

 

Can you please let me know if this "link" which exists in Metadata and carries through replication works on previous versions like Teradata v14.10 (bear with me) ? Does it depend on the database version at all ?

 

Abhi, just curious about the feature which you have heard about in 16.20 ?  How does BAR recognize if it has to use the Full Backup or not ? Does it scan the tables on the database? what if I have deleted off some rows which should be recovered from the FULL Backup ?

Enthusiast

Re: Incremental Restore with Replication

Good question! I think in 16.20 it keeps track of data changes in each block and then when you restore a delta ( assuming you had a full back up earlier) it would compare the blocks from the point of your previous restore and just change those blocks instead of changing every block. My knowledge in this feature is very limited, sorry!