high speed drives

[IT Manager]

The drives mentioned in my original article are now running under SCO
Unix 3.2v2 and they all have AFS file systems on them.  Below are
some updated numbers on their performance.

During the installtion, I made the Micropolis drive the /usr/local and
/usr/spool drive, and it seems to handle having lots of little files
(e.g. /usr/spool/news) better than the Miniscribe did.  But, then again,
this could be due to the AFS filesystem.

In article <790 at tiamat.fsc.com>, jim at tiamat.fsc.com ( IT Manager) writes:
> As far as performance goes, here's some numbers:
> 
> from "time dd if=/dev/XXXX of=/dev/null bs=100k count=10"
> 
> for the Miniscribe 3180S
> 10+0 records in
> 10+0 records out
> 
> real        17.7
> user         0.0
> sys          0.4

under Unix:
real        3.0
user        0.0
sys         0.2

> for the Miniscribe 8380S
> 
> real        17.9
> user         0.0
> sys          0.5

under Unix:

real        3.0
user        0.0
sys         0.3

> for the Micropolis 1684
> 10+0 records in
> 10+0 records out
> 
> real         3.9
> user         0.0
> sys          0.6

under Unix, /usr/spool filesystem:
real       11.1
user        0.0
sys         0.4

/usr/local filesystem:
real        6.9
user        0.0
sys         0.4

>From the looks of those numbers, it seems that the data you have on the
drive (or how it is arranged) can have something to do with the performance
under this type of test.

> On the surface (and definitely under this installation) the Micropolis is
> much faster.  These drives are are installed in their "default" state, so
> there has been no performance tuning.  These drives will be involved in an
> upgrade soon, and before we install the OS, I'll use Roy Neese's SCSICNTL
> program to try to do some fine tuning on the drives.

Well, I tried to use SCSICNTL but kept getting message about not being able
to read something from the adapter.  Oh, well.  So, the only configuring
I did was to re-format these drives using the Adaptec on-board BIOS
routines and specify a 1:1 interleave.

All in all, I still like the SCSI drives and I like them even better under
Unix.
------------- 
James B. O'Connor			jim at tiamat.fsc.com
Ahlstrom Filtration, Inc.		615/821-4022 x. 651