Date: Mon, 6 Dec 1999 10:17:31 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: Matthew Jacob <mjacob@feral.com> Cc: "Jordan K. Hubbard" <jkh@zippy.cdrom.com>, Dan Seguin <dseg@texar.com>, Bill Fumerola <billf@chc-chimes.com>, "Ronald F. Guilmette" <rfg@monkeys.com>, freebsd-hackers@FreeBSD.ORG Subject: Re: Strange SCSI sickness Message-ID: <199912061817.KAA71061@apollo.backplane.com> References: <Pine.BSF.4.10.9912051332220.28920-100000@beppo.feral.com>
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:> treatment, in roughly this order:
:>
:> 3a) Complete check of all cables and the seating of connectors.
:>
:> 3b) Examination of the drive(s) in question for any cooling or
:> mounting deficiencies. Depending on the SCSI errors in question,
:> I might even investigate firmware updates for the drive(s).
:>
:> 3c) Examination of the controller for correct seating and bus slot
:> (in older PCI mobos, this makes a difference) as well as its
:> firmware revision level.
:>
:
:3d) Any system experiencieng scsi parity errors should have all components
: power cycled (for self healing termpwr- fuses) and any pluggable
: termpwr fuses checked (these are exceedingly rare now- but if you
: had a SparcStation, they'd be the first thing to check- they're next
: to the ethernet connector on the motherboard). If you're not using
: an active terminator, you should be. Check for multiple termination-
: both ends of the bus must have termination enabled, nothing else-
: check drive and hba. If necessary, derate off of Ultra to Fast to
: see if this was the source of problems.
:
:[ a parity error indicates trashed signals. a parity error in data phase
:indicates signal reflection, skew, or rise time problems. signal quality
:is greatly affected by: bus length, termination, cable impedance mismatches ]
Only buy terminators with terminator-power LEDs, and only use external
terminators (it makes it easier to maintain the drives).
-Matt
Matthew Dillon
<dillon@backplane.com>
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