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From: ab@distler.maschinenbau.uni-dortmund.de (Andreas Braukmann (NetAdmin))
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: SCSI - throughput
Date: 15 Sep 1995 13:18:52 GMT
Organization: University of Dortmund, LTD II
Lines: 66
Message-ID: <43bufs$ekb@nx2.hrz.uni-dortmund.de>
NNTP-Posting-Host: distler.maschinenbau.uni-dortmund.de
X-Newsreader: TIN [version 1.2 PL2]

Hi everybody,

 ... just for the records.

 A few hours ago I've hooked up a new 4.3 GB disk to my FreeBSD box.


hardware:    i486DX2, 66MHz, 32 MB RAM
             EISA (sis), AHA2742AT,
             sd0: FUJITSU M2694ES-512 812A
             sd1: IBM OEM DFHSS4F 4040 (DHFS 34320 4.3 GB)
os:          FreeBSD 2.0.5 (950622-SNAP)

for the DFHS:
bonnie -s 512
File './Bonnie.295', size 536870912
[...]
    -------Sequential Output-------- ---Sequential Input-- --Random--
    -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
    K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
     1379 98.3  3244 64.0 1448  47.9 1342  98.4 3226  52.3  74.7 9.1 
 
for the M2694:
bonnie -s 96
File './Bonnie.385' size: 100663296
[...]
    -------Sequential Output-------- ---Sequential Input-- --Random--
    -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
    K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
     1367 97.5  1855 28.8   998 34.1  1339 98.1  2669 42.6  57.7 6.8


hmm, it seems, that the character i/o is constrained by the cpu.
I've switched from an AHA1742A to the 2742AT a couple of months ago. 
Unfortunetly I have no exact 1742 based bonnie results for comparison, but
as far as I remember the 1742A(driver) gave better character i/o throughput,
especially it didn't eat that much cpu-cycles.

Have a look at the iozone-results.
(Same machine, 16MB RAM, disk is the Fuji. 2694)

1742:  1973790 bytes/second for writing
       2966137 bytes/second for reading
time: 0.5 u  21.9 s  0:28.72 78,3%

2742:  1760232 bytes/second for writing
       2542905 bytes/second for reading
time: 0.6 u  29.7 s  0:32.52  93,3%

Should I switch back to the 1742? As I need the two SCSI-channels, I would
have to find a second 1742, ... and that does'nt seem to be that easy these 
days ...


Greetings,
     Andreas

P.S. ... sorry, ... English is not my native language ...

--
       +------------------------------------------------------+
       | Andreas Braukmann             University of Dortmund |
       +------------------------------------------------------+
       |       braukman@ls12.informatik.uni-dortmund.de       |
       |       ab@ltd2.maschinenbau.uni-dortmund.de           |
       +------------------------------------------------------+