BE 2012: Test Run & Pre-Scan?

[MIXIT]

Hi all.  I"m still reading through the BE 2012 admin guide so am learning this product as I go but one thing I read is that in order for the backup job to be able to esetimate the amount of data you have the back up, and the time it will take, you must enable Pre-Scan, which can only be enabled by turning on Test Run. 

The very first time I did this, the server took as long to do the Test Run as it would a normal backup, many hours.  If all this feature does is do some preliminary scans, why did it take that long?  The amount of data was perhaps 1.7TB total, and the tape drive is LTO5. 

Also can anybody advise me: is there a real-world usefullness for enbaling Test Run?  I am assuming by enabling it, your normal backup jobstill runs but this Test Run poriton runs first.  Or by enabling Test Run, are you converting your job from a real backup job to essentially a backup simulation but no real backup occurs? 

Thank you. 

[pkh · Accepted solution]

It is the pre-scan that takes a long time not the test run. There is a warning that you should not turn on pre-scan unless you are willing to put up with the long run time

[Lothar_Müller · Accepted solution]

I dont't use these at all.

Ther may be a usecase in bigger enviroments where multiple Backup Servers and multiple Librarys are installed, but not in smaller ones.

[DNI_1 · Accepted solution]

Hi Mixit,

Pre-scan is the most accurate method of determining media capacity. It is expected to take a long time post which the actual backup starts. It doesn't really depend on the storage to get it completed faster.

Test-Run is almost a backup simulation as you say and it actually enables Backup Exec to scan the scheduled backup job to determine if enough media is available to run the job.

Test- Run is only useful when you DO NOT have Job History. If you have one, you could have a quick check and determine the media usage for that backup job.

REFERENCE: http://www.symantec.com/docs/HOWTO73377

http://www.symantec.com/docs/HOWTO73376

[MIXIT]

Thanks gentlemen.  I admit I am sort of in the small business mindset which is a limiting paradigm to be in.  I can see how if you had several servers and backup devices in pools why you would do this test.  In my case, I have one server (with some VMs) and one tape drive so now I understand why test run isn't much use. 

After having run a few backups and then later disabling test run Id o see that in the job activity log for a current job it now shows the est. time remaining. 

Thanks again everybody.