Synthetic Backup - revealed?

[paro]

Hello.

I wonder if there's someone here who can straight out how sythetic backups really work. Especially which media is replaced with which and so on.

I've been running a 10.1 (b5629) installation and I'm getting kinda confused with this particular concept.

Here's how I've set one of my policys up (Not. This policy only run standard file-based backups from 17 different servers, there are no DB's whatsoever involved here):

I have used the built-in Media Rotation Policy to let BE perform,
* a baseline backup to disk (runs only once, collecting additional information for synthetic backups)
* then the backup runs incremental backup jobs (with collecting additional info for synthetic backup)
* every weekend BE should perform a synthetic full backup to disk with a following duplicate job to push the freshly made synthetic full backup to tape - it's this particular part I'm having trouble understanding.

So heres the drill-down:

One baseline backup + 4 incremental jobs are all backed up to the same b2d folder. What will happen when the weekend "create weekly synthetic full backup" runs (this job has the same b2d folder set as both baseline + the following incremental jobs)?

In my humble opinion I thought that the weekly synth. full backup job would merge the baseline with the 4 incremental jobs leaving me with one freshly NEW "baseline" to use for the next weeks synthetic full job AND freeing up space on the b2d folder.

Unfortunatelly for me, this doesn't seem to be the case. The space on my disks are running out to quickly so I figured that maybe I wasn't "getting" the concept of sythetic backups.

So, are synthetic full backups a merge of baseline + incrementals or does the synthetic backup take up double the space?

Is there someone that can straighten out this for me?

Best regards,

Patrik

[tejashree_Bhate]

Hello,

Please refer to the technote given below.

(title) How to create a Policy for a Synthetic Full Backup job in Backup Exec 10.0

http://support.veritas.com/docs/270015

Note:- if we do not receive your reply within two business days, this post would be assumed answered and archived.

[paro]

> Hello,
>
> Please refer to the technote given below.
>
> (title) How to create a Policy for a Synthetic Full
> Backup job in Backup Exec 10.0
>
> http://support.veritas.com/docs/270015
>
> Note:- if we do not receive your reply within two
> business days, this post would be assumed
> answered and archived.

Hi again,

if this is your answer to my question I cannot believe you actually read my original post.

I'm very dissatisfied with this reply, please try again!

In short - I need an explanation of how the synthetic full backups actually are being created....well, it's all there in my original question.

/Patrik

[shweta_rege]

Hello,

A synthetic backup can only be created in a policy.
There are different methods you can use to create a policy that contains the necessary job templates for a synthetic backup:

1. Use the Policy Wizard. See Creating a Synthetic Backup By Using the Policy Wizard.

2. Make a copy of the synthetic backup policy example and then modify the job templates to suit your specific needs.

3. Manually create a policy, and then add the necessary job templates for the synthetic backup feature.

According to the function of Synthetic backup you need to perform Incremental Backup in "Backup-to-disk" folder (On disk) whereas Synthetic Full backup on Tape or disk.


- Kindly refer the following Documents for the same

How to create a synthetic (catalog driven) backup job
http://support.veritas.com/docs/276170

How to create a Policy for a Synthetic Full Backup job in Backup Exec 10.0
http://support.veritas.com/docs/270015


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Note : If we do not receive your reply within two business days, this post would be marked ‘assumed answered’ and would be moved to ‘answered questions’ pool.


Thanks.

[paro]

> Hello,
>
> A synthetic backup can only be created in a policy.
> .
> There are different methods you can use to create a
> policy that contains the necessary job templates for
> a synthetic backup:
>
> 1. Use the Policy Wizard. See Creating a Synthetic
> Backup By Using the Policy Wizard.
>
> 2. Make a copy of the synthetic backup policy example
> and then modify the job templates to suit your
> specific needs.
>
> 3. Manually create a policy, and then add the
> necessary job templates for the synthetic backup
> feature.
>
> According to the function of Synthetic backup you
> need to perform Incremental Backup in
> "Backup-to-disk" folder (On disk) whereas Synthetic
> Full backup on Tape or disk.
>
>
> - Kindly refer the following Documents for the same
>
> How to create a synthetic (catalog driven) backup job
>
> http://support.veritas.com/docs/276170
>
> How to create a Policy for a Synthetic Full Backup
> job in Backup Exec 10.0
> http://support.veritas.com/docs/270015
>
>
> ******************************************************
> ************
> ******************************************************
> ***********
>
> Note : If we do not receive your reply within two
> business days, this post would be marked ‘assumed
> answered’ and would be moved to ‘answered questions’
> pool.
>
>
> Thanks.

Hello again,

Ok, this was a slighly better answer but I still think my original question hasn't been answered.

I am still wondering what happens in terms of space consumption if my backup-to-disk folder with the first baseline backup after the synthetic full backup has been performed.

Will the synthetic full backup to disk REPLACE my original baseline?
And will the incrementals disappear and freeing up space when the syntetic full successfully has been carried out?

For your record, neither of the documents in your last reply was able to answer my question.

Regards,

Patrik

[Renuka_-]

Hello,
The synthetic backups will not replce the baseline full backup, the baseline backup is in fact required for restore along with the latest synthetic backup.
NOTE : If we do not receive your reply within two business days, this post would be marked assumed answeredand would be moved toanswered questions pool.

[paro]

Aah Renuka!

At last, a straight answer to my fairly straight question.

Thanks,

Patrik