I believe the filesystem I/O is buffered using Veritas. Is there an easy way
to find out?
"Yong Huang" <yong321_at_yahoo.com> wrote in message
news:b3cb12d6.0106201048.12d3a771_at_posting.google.com...
> This is what Steve Adams says:
>
> This is what the Ixora web tip on multiblock reads at
> http://www.ixora.com.au/tips/creation/multiblock.htm says on the matter
...
>
> "Unfortunately, if you use buffered I/O the operating system will service
> multiblock reads as a series of small I/O operations anyway and the only
> benefit
> from multiblock reads will be a small saving in CPU usage. In this case
the
> multiblock read count should be approximately equal to the typical track
length
> to take advantage of track buffering and no larger lest the optimizer be
> deceived."
>
> The key word there is "buffered". If your filesystem is able to do direct
I/O,
> and is configured to do so, then the large multiblock read principle
applies.
> But, if your filesystem I/O is buffered, then there is very little to
gain.
>
Received on Wed Jun 20 2001 - 14:18:23 CDT
