News Group Posts

dual shared scsi

From: Roberto Zini <r.zini@strhold.it>
Subject: Re: Dual shared SCSI device
Date: Thu, 28 Mar 2002 12:49:21 +0100
References: <3C9A0139.F654E1F9@strhold.it>
<3c9a468b$0$23184$79c14f64@nan-newsreader-03.noos.net>
<3C9AE6FD.4115026E@strhold.it>
<55de11a6.0203220817.3593d112@posting.google.com> 

steve overy wrote:
> 
> Roberto Zini <r.zini@strhold.it> wrote in message news:<3C9AE6FD.4115026E@strhold.it>...
> > John Hughes wrote:
> > >
> > > "Roberto Zini" <r.zini@strhold.it> a �crit dans le message de news:
> > > 3C9A0139.F654E1F9@strhold.it...
> 
> etc...
> 
> In general it should work, certainly we have sites doing stuff like
> this (ie disks shared between systems).
> 
> Question, are you using a scsi "Y" cable or individual cables from
> each of the systems to a dual ported disk unit?
> 
> This sounds a bit like scsi termination type stuff. We sometimes use
> independent "active" scsi terminators to fix the "powering down a
> system" problem.
> 
> Question, what sort of scsi cable lengths are you using?
> 
> You have "SCSI reset" disabled - I have rx'd comment that says modern
> drivers should be able to cope with (the remote node starting up &
> sending a reset). However which modern drivers implement this is more
> of a question. Disabled is probably safe enuff!
> 
> Not certain about the "register with vxvm" comment - you dont need to
> put the disks under ODM control, certainly there are excelent reasons
> for so doing, but you dont "need" to. I have reliant sites that do not
> use ODM.
> 
> I wonder if the "sdighost" command would reveal anything... I suspect
> not since the fault is very low level (hardware not recognised), but
> might be worth a whirl.
> 
> I assume that if you turn off either system the disks are recognised
> by the other system?
> 
> steve

[My ISP's news server has been playing up lately so dunno if the following
actually got out so here it comes again]

Steve and John,

thank you for your hints !

I eventually tracked down the problem thanks to the invaluable support
I got from Caldera (before starting a flame war I'd like to point out that we
DO PAY a lot of bucks for their support so don't start complaining about the
lack of responses you might have experienced with them) ; in fact, although I 
created a valid Unix partition on the shared disk, I forgot to create a valid 
__filesystem__ on it :-(

Thus making, the first booted OpenUNIX8 did search for a valid VTOC scheme on the
external storage and it locked out other SCSI requests from the second
machine (and that was a known issue they made me aware of).

As soon as I created (by using "diskadd") a valid filesystem slice and
rebooted (just to be sure) both boxes, they were able to "see" the
shared device without the "device busy" message.

I also tried to mount the filesystem on a box (which succeeded) but when
I tried to do the same on the second one, I got an "inode corruption"
message and the operation failed (but that was expected since OU8 does
not have a kind of "global filesystem" support).

So the key point is to creare a valid __FILESYSTEM__ (an Unix partition
will __NOT__ suffice) before even trying to access the shared disk
(even with fdisk).

Hope this helps !

Best,
Roberto
-- 
---------------------------------------------------------------------
Roberto Zini                                email : r.zini@strhold.it
Technical Support Manager -- Strhold Evolution Division  R.E. (ITALY)
---------------------------------------------------------------------
"Has anybody around here seen an aircraft carrier?"                
        (Pete "Maverick" Mitchell - Top Gun)
 

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