Date: Thu, 14 Oct 1999 15:53:13 +0100 (WEST) From: Joao Pagaime <jpsp@rccn.net> To: scsi@freebsd.org Subject: FreeBSD 3.2 / Slow SCSI Dell PowerEdge 4300 Message-ID: <Pine.BSF.4.10.9910141552550.15842-100000@atlas.rccn.net>
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Hi all
I have a very slow Pentium III/450 with 512MB RAM
because disks tranfers are slow.
Simple tests show a transfer rate of +/- 2MB/sec,
when a PC with IDE can do easily at least 4 times
that value.
I think the problem is with the "Common Access Method"
in the backplane, because although the controllers are
found with no problem :
ahc0: <Adaptec aic7890/91 Ultra2 SCSI adapter> rev 0x00 int a irq 11 on
pci2.4.0
ahc0: aic7890/91 Wide Channel A, SCSI Id=7, 16/255 SCBs
ahc1: <Adaptec aic7860 SCSI adapter> rev 0x03 int a irq 11 on pci2.6.0
ahc1: aic7860 Single Channel A, SCSI Id=7, 3/255 SCBs
The backplane is reported as having only 3.3 MB transfer rate :
pass2 at ahc0 bus 0 target 6 lun 0
pass2: <DELL 1x6 U2W SCSI BP 5.12> Fixed Processor SCSI-2 device
pass2: 3.300MB/s transfers
Did anyone experience the same problem ?
Can someone help me ?
Any hints ?
Any configurarion at the CAM level ? - I configured the kernel
to debug CAM but I can only reboot the machine in a few
hours...
Thanks,
Joao Pagaime
PS: the disks are also reporter correctly :
da1 at ahc0 bus 0 target 1 lun 0
da1: <WDIGTL WDE9180 ULTRA2 1.20> Fixed Direct Access SCSI-2 device
da1: 80.000MB/s transfers (40.000MHz, offset 31, 16bit)
da1: 8687MB (17793001 512 byte sectors: 255H 63S/T 1107C)
da0 at ahc0 bus 0 target 0 lun 0
da0: <WDIGTL WDE9180 ULTRA2 1.20> Fixed Direct Access SCSI-2 device
da0: 80.000MB/s transfers (40.000MHz, offset 31, 16bit)
da0: 8687MB (17793001 512 byte sectors: 255H 63S/T 1107C)
And here are a few miserable tests :
Sparc Entreprise 1000 - very old :
time dd bs=1000000 count=100 if=/dev/zero of=t
100+0 records in
100+0 records out
real 0m22.640s
user 0m0.055s
sys 0m16.094s
Dell PowerEdge 4300
(http://www.dell.com/products/poweredge/pe4300/index.htm)
time dd bs=1000000 count=100 if=/dev/zero of=t
100+0 records in
100+0 records out
100000000 bytes transferred in 53.853144 secs (1856902 bytes/sec)
real 0m55.553s
user 0m0.001s
sys 0m1.562s
This makes very unhappy users !
thank again,
--
FCCN - Fundacao para a Computacao Cientifica Nacional - Tel: 351-1-8440100
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