Compression on Backup Exec 12.5

We are currently running Symantec Backup Exec 12.5 SP2 on Windows Server 2003, and our compression ratio on our D2T backups is currently sitting at 1:1 or in some cases ranges at 1.5:1 (screenshot 1), as you can see from the screenshot, some of our tapes are running out of space, and with our backups increasing from week to week, we're trying to compress the data on the tapes (HP Ultrium 4 tapes = http://www.frontierpc.com/ProductImages/Large/1010815445.jpg) which as far as i can find, can handle compression. All our jobs have compression turned on (screenshot 2), but after following these instructions from Symantec = http://seer.entsupport.symantec.com/docs/287662.htm the Tracer program shows that the backups are NOT compressed (screenshot 3). Anyone have any ideas how i can go about compressing the B2D portion of our backups?

FYI we backup about 12 servers, from policy they backup to tape, and then we run a duplicate to tape.
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tlcsupportAsked:
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L3370Commented:
The amount of compression you get depends entirely on the type of data you are writing to tape.  Databases, text based files or data that isn't already compressed will have very successful compression ratios....I've seen 4:1 and even 10:1 ratios when backing up only this type of data.

If you are backing up large amounts of files such as jpegs, zip files, mp3's or other already compressed media, your success will be little.

The compression capability advertised on the tapes and your backup systems are completely theoretical, and more often than not are impossible to reproduce even in perfect conditions. I wouldn't bet on compression capacity for planning your backups.

You also have to see what your Tape library is rated for as well.
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L3370Commented:
to make sure your tapes are being used to its full compression capability, make sure each tape is correctly identified by type in BE

Right click on one of the tapes in the media set, select properties and click the button next to Media Type. There will be menu's to select which type of tape it is.
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glenn_1984Commented:
In BE, Devices, Right Click on Drive Name,
Properties
Configuration
Is Compression Enabled?
I had to reset mine to:
32k
32k
10
1
Uncheck ALL boxes
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Thomas RushCommented:
I'd appreciate info about specific HW you're using -- which manufacturer and tape drive model?  Which HBA?  Firmware revisions on those might help as well.

Your backup-to-disk (B2D) portion will have to be  compressed in software, unless you're using a target device such as a VLS that has compression built in to it.  Be aware that SW compression is very CPU-intensive and may slow down the speed of your backups.

If you've got your B2D compressed, then how you get that data to tape determines if it's going to be zero compressibility, or whatever the underlying files naturally are.  Compression is all about finding patterns in your data and replacing those recurring patterns with tokens, in a process that can be 100% reversed when the data is decompressed.  But if the compression is effective, it's removed all the patterns, so that the second time you try to compress, there will be very little or no patterns left to find, and your compression will be close to zero (I've even seen it negative -- the file gets bigger with the second compression -- due to the overhead of the compression metadata).

So -- if you backup your compressed B2D *as files* to tape, you'll see no further compression on tape.  (This has another Really Bad Side Effect, which is you have to restore from tape to get the B2D files, then you have to restore from the B2D store -- restores take at least twice as long as they would direct from tape).

If you do a "copy to tape", where the backup application knows it's essentially creating a copy of a previous backup job to different media, then the data will be decompressed on the server (again, look for a spike in CPU use), and then compressed by the HW of the tape drive (no server CPU cost).

If you have the space on your server, I'd suggest doing a backup-to-disk uncompressed, followed by a copy-to-tape, with HW compression enabled on the tape drive.   Some files will compress, some won't (as Leeto says, above); customers tell me that the average compression they see is 1.3:1.

You as a user have no control of how compressible your files are -- other than knowing that compressing them before they get to tape will give you zero compression.

One other thing; I note that some of your tapes are showing 390GB; if those are really LTO-4 tapes, check to make sure you've used the correct barcode labels, which should end in L4, not L3.

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