SUMMARY: SCSI & file system usage benchmarks

From: Henrik Schmiediche (
Date: Wed Mar 13 1996 - 14:23:47 CST

Thanks to all who responded. My questions was:

>Does anyone know of a way to measure if the SCSI bus is being
>saturated on a regular basis? I know the max throughput of the BUS
>(Sparc 10) and I know that in theory 3 Fast SCSI-2 drives could
>saturate the bus, but I'd like to know how often this actually is a
>problem on my system.
>Also, does anyone know how to measure file system usage? Eg. which
>files systems are being most heavily used. One tool is nfswatch, but
>that does not include local file system usage.

There does not seem to be any utility that measures SCSI BUS
saturation. Some people suggested using "iostat -x" (which works on
Solaris 2, but not on SunOS 4). Iostat is a good tool for diagnosing
and monitoring disk I/O and I use it for that, but it does not
directly deal with SCSI bus saturation. Anyone know of a "iostat -x"
equivalent for SunOS 4?

Several other people suggested that with 3 SCSI drives it was very
unlikely that the bus would be saturated since most disk I/O in
multiuser systems is dominated by seek and rotational latencies -
transfer rate is seldom the bottleneck.

I received no answers to my file system usage query.

Thanks to all who responded.

     - Henrik

Henrik Schmiediche, Dept. of Statistics, Texas A&M, College Station, TX 77843
E-mail:  |  Tel: (409) 862-1764   |  Fax: (409) 845-3144
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