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Hardware compression problems

ojidehen
ojidehen asked
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Arcserve is performing compression at the hardware level and for some strange reason the data compression that was formerly stored on a single tape is now being stored on 2 tapes.
Arcserve is performing the backup and compression on 2 tapes.

What can i do to resolve the problem?

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Most Valuable Expert 2015
Commented:
Maybe the amount of data you are backing up has increased so it doesn't fit on just one tape anymore?

Or if you have used the same tape over and over, it wears with time and the available space is reduced.

Also, whether the data can be compressed and by what level depends on the data. Some data isn't compressible while other data can be compressed more. Zip files, pictures, videos etc can't be compressed, and those are usually also already very large files, while text documents etc can usually be compressed a lot, but again those files are usually small to begin with.

Further, it is possible your tape drive is failing...

Author

Commented:
The data increased by about 20GB, not enough to occupy two tapes
Most Valuable Expert 2015

Commented:
Why not? 20GB is quite a lot. What types of tapes are you using? What is the total GB's you are backing up?
Not to mention that MPEG's, ZIP's, and other compressed files get larger when they are recompressed.
And yes; what are the tapes?

Author

Commented:
Tape Drive:   HP Ultrium3-SI     firmware version:  C25W
Library:   HP MSL2024
SCSI Card:   Interface drive SAS
Most Valuable Expert 2015
Commented:
What about the other Questions we had, like what are you totally backing up, and are you also using ultrium3 tapes, or are you using lower capacity tapes, as it is backwards compatible? And what types of data are you typically backing up? How old are the tapes you are using?

From Experience I'd never expect a 2:1 compression ratio, even if the manufacturers advertise that. For your example with a 400GB Tape, which according to the manufacturers has a compressed capacity of 800GB, I'd expect more like a max of 600GB or less to fit on a tape, particularly if you backup a standard mix of data.

Author

Commented:
I am using Ultrium 3 tapes. Backing up a file server - office docs, database sql, active directory. And I have been using tapes since March of this year.
Most Valuable Expert 2015

Commented:
You still haven't told us the size you are backing up.
I agree with @rindi, LTO-3 is 400GB, 1.7:1 compression is usually the best you can expect to achieve so 600GB ish  is where i would expect you to be to fill a tape.

But unless you give us the stats on what backups used to look like before you added the extra 20GB and also after we cannot advise you on why it might have gone to 2 tapes.

Author

Commented:
625000MB
62.5GB?

What does the arcserve backup log look like?

Author

Commented:
605GB

Author

Commented:
Not 62.5GB
Sorry got the wrong glasses on!

So 600 GB, that's in the ballpark for a full LTO-3 tape!

Is that a single tape capacity or a 2 tape capacity?

Why are you being so reticent in your replies? just giving us the minimum required?

Author

Commented:
Sorry, Just getting used to using this, I am actually sending the info on behalf of aa friend... The info that I have says that the Hard drive size is 130GB. So I am thinking that should be a 2 or 3 tape capacity...hope this helps
1300GB maybe?

Author

Commented:
LTO3 with a capacity of 400GB and 800GB compression of  Hardware 2:1.


Author

Commented:
Does anyone have an Idea what the problem is?
You told us you are backing up 605GB which is probably enough to fill a LTO-3 tape, adding another 20GB is probably going to push it over the top and run onto two tapes. If that is what the problem is?




You are still being very economical with your questions and we are having to guess what you are trying to ask! Think about it this way - Think about trying to explain the problem to your grandmother!