Hello managers,
this morning i've installed into my alpha 3000/400 (turbochannel)
a new double scsi-interface (PMAZC-AA) and configured it to use the FAST
scsi mode. Anything seems to work fine.
Then (and before) i did some testing. This machine now has the internal,
the external and 4 additional scsi-interfaces (2 * PMAZB-AA, 2 * PMAZC-AA).
My simple test is as follows: i copy /vmunix (about 9.8 MB) ten times to
one of my disks and measure the time with the csh-builtin time command.
This i do ten times and then i "built" from this a mean value.
My disks are digital (dsp5200, dsp5350, dsp5400) and seagate (st15230n)
and all of them claim to be able to use FAST scsi.
Okay, this night (with only slow scsi but on an idle machine) my mean values
range from 43.2 sec to 29.7 sec meaning something like 2.2 to 3.2 MB/sec.
I think the differences result mainly from how full my disks are; there is
one that is empty and that has the fastest result.
Now today i attach to each of the new fast scsi-interfaces only one disk and
my mean values, copying from slow-disk to fast-disk range from 24.8 sec
(3.86 MB/sec) to 38.0 sec (2.52 MB/sec). And copying from the one to the other
fast disk gives 30.7 sec (3.12 MB/sec) and 36.3 sec (2.64 MB/sec)
Running the monitor-utility while copying shows maximum transferrates of
only about 4.3 to 4.5 MB/sec.
Is there something wrong? Why don't i see much higher values? At least for
the latter i'd expect something between 7 and 9 or 10 MB/sec. Is 5 (or 6)
scsi-buses (with 17 devices most of them nfs-exported) to much for my turbochannel?
Any hints or ideas?
Thank you!
Bernt Christandl
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- Bernt Christandl / Max Planck Institut fuer Extraterrestrische Physik -
- D-85740 Garching / Phone: +49/89/3299-3342 / Fax: +49/89/3299-3569 -
- Internet: beb_at_mpe-garching.mpg.de -
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Received on Tue Feb 11 1997 - 12:35:14 NZDT