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Symantec Backup exec compression issue

Hi,

I have been using Symantec Backup Exec V12 on a windows 2003 server 32 bit. I have installed a HP ultrium 3 SCSI 800GB tape drive. My full backup sixe is just over 500GB. Every day i run the backup is request another tape before it gets to 500gb of data?

I have installed the latest HP and Symantec drivers and used hardware and softare compression, but still it asks for another tape to complete backup? I have my media set to overwrte.

When i check the compression i am getting 1.1:1 or sometimes 1.5:1, but still asks for another tape?

I have replaced the drive, but still the same issue and updated Symantec backup exec to 2010, but still the same issue.

Help please? any ideas why it is doing this?
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monarchit
Asked:
monarchit
1 Solution
 
g000seCommented:
Hi.

You may have seen this article http://seer.entsupport.symantec.com/docs/199542.htm
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WolfhereCommented:
From the Console, to confirm read/write is yes for the LTO (all types) under Devices, highlight the tape drive, Properties. there will be a list and the opportunity to tick for each highlighted type. Also, run your cleaning tape about 3 times in succession. The heads glazing could affect how BE sees the tape type.
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JBond2010Commented:
Do have a time scale for when the backup finishes eg: 8 hours?
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monarchitAuthor Commented:
No
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SelfGovernCommented:
1) Those Ultrium 3 drives (all manufacturers) are 400GB native, and the 800GB capacity is only if your data compresses at 2:1 or better.   You have no control over how compressible your data is.  Some files compress well (text files), some compress poorly or not at all (jpeg, mpeg, .ppt, encrypted files).

2) So if you have 500GB of actual data, it will have to compress over 1.25:1 to fit on a 400GB tape (there's metadata overhead when you back up; complete path and file name as well as attributes and ownership/permissions) must be stored for each file.

3) While you can't make your data *more* compressible, you can make it *less* compressible -- for instance, by encrypting it using your backup application.  Make sure you're not doing this.

4) It's possible that a dirty head or poor quality media could mean you fit less data on a tape.   Using the cleaning tape once or twice will clean the head; making sure you're using HP-branded media will make sure you're not using cheap media.  

5) Since this is an HP tape drive, you can download HP's free Library and Tape Tools to run diagnostic tests on the drive and media to make sure things are working correctly.  You can also generate a support ticket that will help HP support figure out if it is a hardware problem.   See
   http://h18006.www1.hp.com/products/storageworks/ltt/

6) HP LTO-3 and later  tape drives have a much more real-time monitoring tool that you can find out about under http://www.hp.com/go/tapeassure -- it can show you real-time compression, performance, tape capacity used, etc.   Very nice, but for standalone drives it does require loading Command View for Tape Libraries (CVTL) which, while free, is not a small download.

7) I think that JBond was asking how long your backups were taking (which must have some value; you can find out by looking at the job logs), not whether you have a backup window.
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