De-duplication option in backup exec

[Khalid_Mashaykh]

I have some concerns regard the dedupe. in backup Exec , I summarized them as below :

• The de-duplication folder create a new medias every time (about 8 medias each one 50 GB size ) in fact that there is available space in the old ones (see the screenshot)

so if this is happened by design and if there is a workaround to utilize the free spaces? 

• Is it doable to recover the de-duplication folder from damaged backup exec server to an alternative one?
• I noticed that the job rate for the BE jobs in VM while the Dedupe is the backup destination is very slow, who facing same problem?

Thank you

[Backup_Admin2]

Really good questions, and I am eager to know the answers/ solutions soon.

[pkh]

The space within the dedup folder is managed by the dedup engine.  There is a twice-daily maintenance job which will re-claim used space within the OST files which are no longer needed, but the actual space occupied by these files will not be freed up.  This is by design.  You cannot do anything about this.

You can backup the dedup folder by backing up the shadow copy component.  See this document

http://www.symantec.com/docs/TECH143335

[Sush---]

When you run a job to Dedupe folder it created the OST files in a virtual or dynamic manner. Meaning if 8 files of 50 GB are created it is not going to actually take 400 GB on the physical disk. The disk space utilised on the physical disk will be equal to the amount of data actually backed up.

So fr example if 8 files are created each of 50 GB  (50*8 = 400 GB) and if the data backed up is only 250 GB then in actual only 250 GB on the hard disk will be used.

Also the remaining 150 GB is virtual and can not be used for any other job because when the backups are taken to Dedupe its always "Overwrite" operation and not "Append" operation. So if the OST are expired (when it passes the Overwrite Protection Period) then it will be overwritten and the space will be reclaimed. If there are no overwritable OST then new one will be created.

Thanks,

-Sush...

[Khalid_Mashaykh]

Thanks PKH and Sush for the reply. This is well understood.

And regarding the Backup Exec Deduplication Folder (suppose it a SAN volume) , if the orginal BE server crashed can I restore the dedupe data by create another BE server and map the dedup folder on it then catalog this dedup folder?

Thank you.

[pkh]

You cannot do this because when you try to define the dedup folder on the volume with the old dedup folder, there will be an error.  You can only have one dedup folder per media server.

[Nick_Elmer · Accepted solution]

With Backup Exec 2010 R3 and higher, you can import a Deduplication folder into an existing installation. So, if your folder is on a SAN, and the old media server fails, then you could make the SAN storage visable to a new server, and import the folder to a new BE installation.

See the following technote for more details.http://www.symantec.com/docs/TECH160832
 

Hope this helps,
Nick