LTO-3 poor write performance

[richard mccarthy]

I have an LTO-3 (HP Ultrium 930) drive attached to an Adaptec U320 controller on a server running Linux.

I’m currently writing 30000 files to tape using GNU tar. Each file is being written as an individual tar (client request),
and each file is around 10MB. I’m getting a write speed of around 1.7MB/s. If I don’t tar every file I get a write speed of around 10-15MB/s.

I’m wondering if the latest firmware 2.0.0.6 (15 Apr 2009) would have larger buffering enabled, which would help increase the write performance?

I have tried larger tar blocks and increasing the mt setblk size and setting the st module buffer size but none made any difference.

Thanks ,
Richard.