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Re: [PLUG] More SCSI Weirdness
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Active termination is better than passive but both exist.
Here's what I know is a nutshell:
Both ends of the bus must be terminated but no other device in the bus should be
terminated.
Example 1:
T---------+---------+----------+-------+-------T
SCSI drive drive drive cable end
adapter
Alternatively, last drive has termination set on:
T---------+---------+--------+-------+-------T
SCSI drive drive drive
adapter on cable end
(+) is connector
(T) indicates termination point.
Incorrect or missing termination causes "ringing" on the bus and might cause
this kind of error.
Eric
jazzman@exdomain.org wrote:
> Both the card and case claim auto termination, but I also have a
> terminator (marked active terminator... is there a "passive" kind?) that
> I've tried... same behavior...
>
> On Sun, 9 Dec 2007, Eric wrote:
>
>> Hey, I'm no SCSI expert but this has a certain "oddness" that might be explained
>> by improper SCSI bus termination.
>>
>> Have you checked that?
>>
>>
>> Eric
>>
>>
>>
>> jazzman@exdomain.org wrote:
>>> Ok, so I think I may have some more info on the weird drive behavior I was
>>> seeing with my scsi array.
>>>
>>> I tried the drive array on a second machine, different OS (Fedora 5) but
>>> the machine behaves similarly (doesn't always detect ALL of the drives on
>>> each boot... the scsi drives randomly pop in and out of existence on each
>>> reboot). The only thing I did notice is that each machine has the SAME
>>> scsi card (tekram DC395x) and that when the drives disappear on the FC5
>>> machine I get the following error message flooding the logs:
>>>
>>> dc395x: QUEUE_FULL for dev (0X-0)
>>>
>>> where X is the scsi ID of the first "missing" drive.
>>>
>>> Does anyone know anything good/bad about this card? It was cheap when I
>>> bought it, but I'm hesitant to go buying new cards/cables and such without
>>> knowing for sure. If this is a "could be anything" type of problem I have
>>> a feeling the scsi case and it's drives end up on ebay befoer long...
>>>
>>> any thoughts?
>>>
>>
>
> ___________________________________________________________________________
> Philadelphia Linux Users Group -- http://www.phillylinux.org
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--
# Eric Lucas
#
# "Oh, I have slipped the surly bond of earth
# And danced the skies on laughter-silvered wings...
# -- John Gillespie Magee Jr
___________________________________________________________________________
Philadelphia Linux Users Group -- http://www.phillylinux.org
Announcements - http://lists.phillylinux.org/mailman/listinfo/plug-announce
General Discussion -- http://lists.phillylinux.org/mailman/listinfo/plug
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