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No compression on backup exec 12.5

Hi.  I'm backing up a couple of servers to a backup exec 12.5 server running Server 2008 and using an HP Ultrium 1760 with HP LTO4 tapes.   All running fine until the 7th - it backed up 941GB of data that night.  Since then it's failed consistently.  The tapes show a maximum capacity of 781.5GB, which is no compression at all, isn't it?  Looking at some of the tapes that haven't been used since the 7th, they've reported compression of between 1.4 and 1.9:1, so I'm guessing this is an issue with the drive or the software rather than the media.  Compression's enabled on the drive

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 I've tried updating the drivers on the tape but I still can't get the tape to accept more than its uncompressed limits.  Thanks.

 
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thanks.  the job has compression set:

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I'll try that tool, cheers.
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Thanks Andy.  Useful tool that.  The drive's faulty and HP are swapping it out.
Probably head wear, it gives the impression of no compression or at least not getting enough data on a tape since it re-writes any bad data further down the tape so taking up more room. LTO4s are pretty hard to feed data to fast enough to stop them continually repositioning (shoe-shining) which wears the head out.
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that's interesting.  It'll be good to swap it out and see immediately whether I can get the compression back again.  To be honest, even compressing at 1.4:1 I'm not getting enough backed up, so I'm thinking about buying an LTO5 device.  Had a brief think about offsite backup, but it's ludicrously expensive.  thanks for getting back to me andy.
Trouble with LTO5 is they're even faster than LTO4, 47-140 MB/s data rate matching meaning that the head should be fed at at least 47MB/s which means about 100MB/s to allow for compression. Can you read your disks at 100MB/s? L&TT has a host test to see if it can.
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Hmm.  It's reading/writing at 82 MB/s as per the test.  Is there any way of improving this?  I must get some sort of improvement off an LTO5, even with this issue.  To be honest, even with 1:1 compression, starting at 1.6TB would be enough for a while.  Anything else is just bonus.  Thanks for the followup questions.
Only way I know of improving the disk read speed is to buy more of them, we often setup D2D2T with several disks in the staging area to ensure we can feed the tape fast enough.