DataMigrator and Backup job clarification required

[simple99]

Hi,
I was hoping someone can help me understand how a CV backup task works when DataMigrator for Filesystem is being used.
The DataMigrator creates stub files on the Primary storage and migrates the actual files to the secondary storage.

When a full-backup is run on the primary storage, does CV backup only the stub files or does is recover the actual files from the secondary storage. ?

If the full-backup only backs up the stub files. Then how is the data pointed by the stubs, on the secondary storage backed up ?

I would like to implement the Datamigrator feature but want to get a clearer picture of whats being backed up and how I can manage the recovery.

Appreciate any info.
regards

 

[Frbutler]

From what I understand the stub is a pointer to the secondary storage via CV as the data mover

so if you double click "A.doc" stub it will create a job within CV to move the data from secondary storage to the primary/original location.

If it has been aux copied off of secondary storage to tape it will require a tape recall/import.

in a d2d2t scenario that is how it would work.

 

[cabraun]

Frbutler's response is correct, although it did not exactly answer the question at least as I understood the original question, which was how is the original data, once migrated, backed up?

Well the answer is, it is no longer backed up, once it is migrated.

The typical scenario as Frbutler laid out is:

Data is moved from high cost storage and replaced with a stub. The orignal data is moved to low cost magnetic storage and is also Aux Copied to tape where it is retained for however long you need to retain.

When full backups run, the stubs only are backed up, not the actual data. That is one of the reasons for using Data Migrator. You are no longer backing up data that is "Archival" or unchanging over and over and over again.

So what happens if the low cost magnetic fails once a bunch of data is migrated to it. You recover from your Aux Copy tapes.

What happens if your low cost mag and tapes both fail? You are SOL!

 

[birky]

Unless you are using SDR to replicate the maglib ;-)



Birky
CommVault Certified Engineer

 

[simple99]

Thanks for the replies.
So the migrated data sitting on the low cost mag storage is backed up as a seperate Aux job which is part of the Data Migrator storage policy.

Does this Data Migration strategy require additional tapes as data is backed to differents sets of tapes for archival?

We have currently have one policy doing a Grandfather, Father, Son backup of data on Primary storage, to tape.
We would require another policy to backup the Migrated data to tape. With different rentention rules etc.

Birky, you mention SDR. What does that stand for.

thanks

 

[birky]

SDR = Simple Data Replication - new feature within SP2 that allows you to utilise Single Instancing to replicate your maglibs. (basicaly it's just CDR that makes use of Single Instancing so you aren't replicating loads of data from your maglib when you run a Full backup).

You are right....for backing up your migrated files you will create an aux copy and give it different retention rules to your primary copy.



Birky
CommVault Certified Engineer

 

[simple99]

I assume the SDR and SP2 are referring to the new Simpana product.

We're looking at upgrading to that sometime in the coming weeks.

thanks for the responses.