DLT8000 Driver for RH LInuxEnterprise4

[Adrian McClatchie]

I have a DLT8000 which will not stream data in 80GB Compressed or uncompressed mode.
It will however stream in 40GB mode.
Is there a driver available? It is not on the support site. I presume Linux has selected a generic SCSI Tape driver.

Thanks for any help.

[Jaclyn Rothe]

DLT 8000 drive is a 40GB native drive, therefore you can expect a 40GB stream. HOWEVER, the burst rate of the drive is only 20mb/s... I would not expect to get 80GB stream to the drive, as this is the compressed (assuming 2:1 compression) throughput.

Throughput, compression and tape capacity are all intertwined.

Basically, if throughput (from the source) is below the minimum specs for the drive the drive will stop and start and/or shoe shine. This causes premature wear to drive, but also increases the amount of time for the back up, can cause bad blocks on the media and thusly there will be less space on the tape. Because the compression ratio is calculated on the space available on the tape with the amount of data written the compression ratio will drop.

Data Set also has everything to do with compression. If the back up has any drawings (CAD files), pictures, PDF docs, video files, these are either already compressed or will not compress. Text compresses extremely well and it is not uncommon to get an all text back up to compress at 2.4:1 ratio

Some useful documents:
HP StorageWorks - DLT and Ultrium Hardware vs. Software Compression
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=lpg50030&jumpid=reg_R1002_USEN

Tape Capacity Differences Prevent Remote Storage from Making Media Copies
http://support.microsoft.com/?kbid=266011

How File System and Disk Configuration Affect Backup Performance
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=lpg50032

Performance Assessment Testing:
http://www.hp.com/support/pat

HP Surestore/StorageWorks- Data Compression Information :
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=lpg50244&prodTypeId=12169&prodSeriesId=42846

[Adrian McClatchie]

Thanks for the response, I think i wrote the first bit wrongly.

It will stream in 20GB non compressed mode but not in 40GB non compressed mode.

It is seismikk data so it is difficult to compress, so compression is OFF.

The drive streams on an XP machine with thru put of 5.88mbs , but not on the RH system