Problems with Hardware Compression C1537A DDS3

[Andi_2]

Hi,

i??ve got a problem with hardware compression on my C1537A.
Hardware Compression oin the drive is enabled but the drive??s storing max. 11GB on my DDS3 Tape with a max write rate of 60mb/min. Why is the rate less data than the native amount of the drive ?

Any Idea ?

I use ArcServe 2000 SP3 on a Win2k Server SP2, the SCSI Controller is an Adaptec AIC7880 UW (also tried with an Adaptec Ultra160)

[Vincent Farrugia]

Hello,

How did you set the switches 1 and 2 (controlling compression)?

Switch 1 should be set to 1 to enable compression. Switch 2 should be set to 1 as well for Host control.

HTH,
Vince

[Marino Meloni_1]

hi
-Conpression of data depend of the data itself, now a days, the data on a server are already optimized and have a low ratio in compression, you can check this, with an utility like winzip, that use a software algoritm to compress data, then compare your data with the result of winzip plus 5 - 10 % value (because Backup Software ad some header and catalogs on the tape).
-Another thing that can create problem is if you have enabled the software conpression, then the data will be sent to the DAT already compressed, then no more compression allowed.
-If you have an old tape or a head problem on your dat, this can worst space due to bad blocks.
-The transfer rate is right, about one Mb/sec id the commom transfer rate for a DDS3 Tape Device.

bye

marino

[harry d brown jr]

Andi,

If you are writing uncompressable files they will actually take up more room on the tape than if you didn't compress the files.

A DDS-3 tape can store 24GB of data PROVIDING it can be COMPRESSED into 12GB.

this means the tape can only really store 12GB!

live free or die
harry