Just a guess -- but I'd ignore the FC transfer size and use a device
blocksize of 128K or 256K (can't remember off the top of my head what LTO
uses as a maximum). The FC transport layer should split/reassemble the
blocks with no problem. For example, our SAP database is FC attached and
Oracle is configured to use an 8K blocksize for all disk I/O -- and that's
been working for several years now.

Tom Kauffman
NIBCO, Inc

> -----Original Message-----
> From: Lars Bebensee [mailto:LBebensee AT HAITEC DOT DE]
> Sent: Tuesday, August 13, 2002 9:24 AM
> To: ADSM-L AT VM.MARIST DOT EDU
> Subject: Tape Performance on 3580
>
>
> Hi guys,
>
> this is actually not a TSM question but one for the hardware
> gurus. We are
> running a backup under AIX using the savevg command and
> Ultrium 3580 tape
> drives. With topas I can see a data transfer rate of about 1MB/sec. We
> attached the drives via Fibre Channel and a SAN Data Gateway.
> The blocksize
> of the drive was set to 2048 (since one of the SAN guys told me FC
> transfers with a blocksize of 2048). I started savevg with
> "-b4" meaning to
> write 4x512Byte blocks (=2048). With the mentioned speed the
> drives are
> seriously crawling. Am I missing out something here? Any clues??
>
> Thanks
>
> Lars
>