"Index from Snapshots" SLP operation

[ddm2]

Hello,

I'm studying the Replicator Director.

The Replicator Director Guide available at this address

http://www.symantec.com/business/support/index?page=content&id=DOC5191

pag. 91-93, describes the "Index from Snapshots" operation.

"Use the Index From Snapshot operation to index (that is, to catalog) snapshots. Indexing a snapshot creates an image .f file for the snapshot in the NetBackup catalog. With the image .f file in place, the administrator can browse and restore files and directories from any copy of that snapshot, even those in long-term storage.

The adminstrator can restore the files by using the NetBackup Backup, Archive, and Restore client interface or the Restore operation in OpsCenter. Use the bplist command to view the contents of the .f file.

Note: Without the Index From Snapshot operation, it is not possible to browse and restore individual files and folders using OpsCenter."

I'm a bit confused about the purpose of this operation.

Can I make granular restore without an "Index from snapshots" operation using the BAR?

When this operation is useful/essential? 

What are main implications in using or not this operation?

I understand that I can make restore of file or directory from a tar file generated froma "backup from snapshot" file. In this situation an "Index from snapshot" operation is useless. Is this correct?

Any info, link to docs, idea or explanation on this topic is very apreciated. 

Thanks.

[RLeon]

Hi ddm2,

If you look into the Netbackup 7.5 Admin guide vol1, under the SLP topics > Replication Operation, you will find all your answers.

The Index From Snapshot operation differs from other operations in that it is
does not create a copy of a snapshot or backup.

We know that it looks inside the snapshot and lists its contents (files) in .f files. I.e., It catalogs the snapshot contents (aka. index).

Use the Index From Snapshot operation in an SLP only once. A restore can be
performed from any snapshot after one image .f file is created.

So if you do an "index from snapshot", you can then restore files directly from the snapshot even before you do a "backup from snapshot".

Any operations list that includes a Backup operation does not need an Index
From Snapshot operation. The Backup operation creates an image .f file.
The only exception is if the index is needed for restores before the Backup
operation occurs.

Since the "backup from snapshot" operation also does the index/catalog thing, there is no point in placing the "index from snapshot" step anywhere after a backup step.

'So then, if the backup step indexes it anyway, what is the point of the "index from snapshot" operation?'
Well, as the guide explains, sometimes you may perfer to have the ability to restore files directly from the snpahost, before the "backup from snapshot" step even begins. If that is the case, then your SLP will contain both an "index from snapshot" step and a "backup from snapshot" step, in that order, but not necessarily consecutively.

So basically, if you index from the snapshot, you can restore files directly from it.
If you backup the snapshot, it indexes it for you anyway, then it copies the snapshot to your preferred storage (AdvancedDisk, Deduplication Pool, Tape media, whatever), then lets you restore files from it. (See? You are not restoring directly from the snapshot anymore; unless you choose to.)

Without any "index from snapshot" or "backup from snapshot" steps in your SLP, you will not be able to restore anything from the snapshot.

I hope that explains it. My brain constructs sentences in a funny way.

RLeon

[ddm2]

Thanks for your precious help.