[3885] in linux-scsi channel archive
Re: changing host ID of ncr53c810?
daemon@ATHENA.MIT.EDU (Harald Milz)
Mon May 11 03:38:03 1998
Date: Mon, 11 May 98 07:10 CEST
From: hm@seneca.muc.de (Harald Milz)
To: linux-scsi@vger.rutgers.edu
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Reply-To: h.milz@seneca.muc.de
Richard Waltham (dormouse@farsrobt.demon.co.uk) wrote:
> Pardon? The SCSI bus needs terminating at each end. If the adaptors are at
> each end then they need terminating or you need external terminators.
That's the point. Please read the HA HOWTO. The adaptors must not be
terminated interanlly if they are at the far ends. You must use something
like a Y cable and use external termination. This is exactly what this
web page says:
> > (http://sunsite.unc.edu/pub/Linux/ALPHA/linux-ha/High-Availability-HOWTO-7.html)
> as at least one device is supplying termpower. I would expect most current
> devices to meet these requirements.
I would "expect" nothing. If the adapters in question work that way - fine,
but - can you be sure?
> The host adaptors need terminating if at the ends of the bus and if external
> terminators are not used. They need to supply termpower to the scsi bus to
> power the terminators at each end of the bus so, if the device at the end of
> the bus, if it has a built in terminator and the device is powered off, the
> terminator remains powered, whether it is a host adaptor or any other
> device.
A lot of ifs. If you are sure about your specific adapter, fine. But this
is not a generic solution.
> Looks like the howto may need updating.
Nope. This is the recommended way all commercial high availability
solutions I know of work.
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