Couple of questions

[CA1157408]

Hi guys,

Hardware is a DLT 80i and Adaptec 39160 (32bit PCI slot/mode)

I have a couple of questions:

I have not been getting great compression. I am using HP C5141F media (DLT IV). The backup only gets to between 37-44 GB before requesting new media. The data is not particulary compressed, but that is not what I really what I need to know.

What I want to try and do is eliminate the hardware, and make sure it is working as optimially as I can get it.

Does anyone know what the ideal settings should be for this SCSI card and drive combination? I am more looking for settings that I would set in the SCSI card to optimise data throughput, etc. Any suggestions welcome.

I have tried setting the speed down to about 40MB/s but am wondering if I should go lower, or maybe leave it at the default of 160.

Next question is related to the LTT utility. The LTT says I am getting about 2.2:1 compression (from the Compression test) and a transfer rate of 7MB/s, but if I create a support ticket and look at the Data Compression value it says "Disabled".

This is under the Detailed Device Information - Drive Configuration Settings.

Is this normal? Am I reading more into this setting than I should?

Thanks in advance for any help/advice.

Kind regards
Garth

[meloni]

1- default value of the scsi hba bios are ok for the dlt80. the transfer rate speed cannot cause any impact until 5 MB/s, so 40 or 80 are the same think for the DLT.
Just select "reset to default value" to be sure

2-if LTT said compression is 2:2.1 so the compression chip inside the DLT is working. the compression can then be put in disable. It have to be se e\nable by the backup sw, there is settings for that.

if you cannot reach hight value of data on your 40/80 cartridge, I would suggest to check in L&TT for R/W errors, running intensive tests, in fact bad tapes or dirty head may cause poor performance and poor cartridge capacity. If everithink is fine, you can just create a know compressible amount of data with the software "CreateData" from HP, exanple 75 MB data with 2:1 compression ratio, and you should be a ble to store them in a DLTiV cartridge