Re: kiobuf using kernel pages

Scott Lurndal (slurn@griffin.engr.sgi.com)
Thu, 18 Nov 1999 18:07:40 -0800 (PST)

> > primarily useful for high-performance disk I/O (e.g. for Oracle)
> > which is not a strength of IDE/EIDE/UDMA devices, and
> > the block device can always be used on IDE devices, it's just
> > slower (and may affect the page cache behavior).
>
> The highest performance I/O devices we support right now are not SCSI
> interfaced at the Linux<->PCI level. Neither the DPT Millenium in I2O block
> mode or the DAC960 are presenting SCSI interfaces.
>
> Alan
>
>

We use fibrechannel here, which is quite high performance, and does
present a SCSI interface.

For other devices, such has single-board hardware raid solutions,
other ways of doing raw character disk I/O will need to be
devised (e.g. the hba/driver for DPT millenium or DAC960 need to
register the appropriate character special device and provide
file_operations to handle the I/O).

Or sct's /dev/raw could be used (where I/O requests
will be broken up into uniform chunks rather single requests
being sent to the host bus adapter).

scott

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