Backup Exec Not Filling Tapes

[dontach]

We are currently using BE 2010 Ver 13.0 Rev 2896 64bit with a Quantum Autoloader that has an 8 tape module installed.  

Our issue is that BE will not fill the tapes or use compression.  Most of the tapes get about 250-300 or less gigs full (LTO-3), but in the device menu the media is listed as Not Appendable(Media full) which is not true.  The current back up is approximately 2.5tb and should only require about 6-7 tapes, but we are having to use 8 which leaves no room for data growth since we only have an 8 slot installed.  With compression we should only have to used 5-6, so any help would be appreciated.

We currently have a media set created that each job is associated with.  Settings are: Infinite Allow Append and Infinite Do Not allow Overwrite.

I have tried many things:

Symantec drivers
Windows drivers
Quantum Drivers
xTalk drive diagnostic
Associating Media Sets
Letting the job pull from scratch
I have checked just about everything in the forum
Software compression/Hardware Compression

I am new to BE, so this could easily a missed check box or something very simple.  Thanks in advance for your assistance.

[pkh]

1) check the job logs to see what compression is being used.

2) after the job is done, go to the Media tab and click on each tape.  Check the compression ratio, Data, Used capacity and available capacity.

Are you using encryption? LTO3 does not support hardware compression so you would have to use software encryption.  If you are using software encryption and hardware compression, you will get a 1:1 compression ratio or even less.

[dontach]

Thank you for the response.

1) We have compression set at Hardware [if available, otherwise software], but it does say Hardware in the log

2) Compression Ratio is 1:1, Data is 200-350, Used Capacity is 400.5, and Available is 0

We are not using encryption, but we have tried Software only compression and the above setting with the same results.

It also states that the Media is Full and not appendable.

[Caleb_Reed]

I've got a very similar setup as dontach and I'm having an identical problem. Encryption is off, compression is on, but it won't actually use compression. Our backup job in 12.5 was using 2 tapes, after "upgrading" to 2010 the exact same job is using 4 tapes.

Any help would be appreciated as this is getting very frustrating.

[pkh]

If you have tried software compression and have a compression ratio of 1:1, this means that your data cannot be compressed.  If you have a lot of movies, jpegs or zipped files, these cannot be compressed.

You can test whether your compression is working by creating a directory full of text files and back this directory up.  You will see good compression ratio.

Another thing to check is that hardware compression is enabled for your tape drive.


 

[dontach]

It does state that compression is enabled; however, even at 1:1 why would my tapes only get 50-65% full.  I have tried both methods of compression and it still will not fill the tapes.

The files that are being backed up are mix of files.  pdf, dwf, doc, eml, many different kinds.

[Ken_Putnam]

There was a problem with v11d and LTO2 way back when v11d came out, with tapes not filling up  ie accepting less than the native capacity

As I recall, the workaround was to use the manufacture's utilty to initialize the tape volumes rather than labelling them in BackupExec

If you do this on tapes that do have data on them, that data will be non-recoverable

{edit to add}

If you try a few passes of the manufacturer's diagnostic utility what does it say about compression?

[MitchR]

Your 1:1 ratio says that you're getting no compression at all. 
When it comes to capacity- all tapes have 2 numbers.  There's the raw (or native) capacity, and then there's the capacity with compression.  The raw capacity is the real size.  Tape salesmen take that number, multiply by 2, then call that the capacity with compression.  In some cases, that can be true- but frequently not.

When you say you're getting 50% capacity, it makes me think that you're looking at the with compression value- and with 1:1 compression, that would be about right.

Compare your tapes with this chart to see if that's the case:  http://en.wikipedia.org/wiki/Linear_Tape-Open#Generations
LTO4, for example, is advertised as 800gb native, 1.6tb with compression.

Now, having said all of that, the reason you're not getting compression is still a mystery.  You may want to run some test jobs without encryption, just to see what happens.

[dontach]

Actually, it is the bytes written that I am looking at.  Most tapes are only reporting 200-350 gigs written which is well under the native capacity of the LTO 3 tapes; that is were I am confused.  We are not getting any compression, and the actual data written is the same size that is reported on disk so we know that the data is getting to the tapes its just taking 2-3 more tapes then necessary.

We do not have any encryption enabled, and the compression is not really as big of an issue (would be nice though), it is the fact that we are wasting about 2-3 tapes with every full backup.  We are currently having to use about 3+ terabytes native (8 tapes) to write just over 2 terabytes of data.  If we could get compression working we could potentially cut the tape number almost in half.

Thanks again for everyone's help.

It is like the data is being expanded instead of compressed.

Ken:

I will try this today since we are in the middle of backups, thanks.

[Larry_Fine]

Re: Actually, it is the bytes written that I am looking at.  Most tapes are only reporting 200-350 gigs written which is well under the native capacity of the LTO 3 tapes; that is were I am confused.

If that tape is showing in BE as "media full" and you are getting less than the native capacity of the drive, then I suggest doing some hardware testing or getting the drive manufacturer involved.  Backup Exec writes to a tape until the tape drive signals that the tape is full, regardless of any capacity numbers that show up in Backup Exec.

[Colin_Weaver]

Hi all

Symantec currently believe that the space issues discussed in this document relate to some problem with the tape drives themselves.  This is because Symantec have been unable to reproduce the problem itself, despite specifically testing with different tape devices and versions of Backup Exec.

Despite being unable to repdocuye, we have do have concerns that there are a small number of issues like this that seem to appear infrequently on the forums. As such if you are experiencing symptoms similar to those discussed in this article when you are using a new tape device, or continue to experience these problems after replacing a tape drive - then we encourage you to log a formal support case for us to research the issue in more detail.

Rgds

Colin

[Hywel_Mallett]

 LTO3 does not support hardware compression  

That should be, " LTO3 does not support hardware encryption". :)