Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 14 Nov 1996 01:13:25 +0300 (MSK)
From:      "=?KOI8-R?Q?=E1=CE=C4=D2=C5=CA_=FE=C5=D2=CE=CF=D7?=" (Andrey A. Chernov) <ache@nagual.ru>
To:        gibbs@freefall.freebsd.org (Justin T. Gibbs)
Cc:        current@FreeBSD.org, scsi@FreeBSD.org
Subject:   Re: SCB paging is most dangerous option now!
Message-ID:  <199611132213.BAA00212@nagual.ru>
In-Reply-To: <199611131606.IAA25507@freefall.freebsd.org> from "Justin T. Gibbs" at "Nov 13, 96 08:06:10 am"

next in thread | previous in thread | raw e-mail | index | archive | help
> >I read only mode I got the almost same result with SCB paging as without it.
> >This bug affects _writing_only_, not reading.
> >And I can't start 8 dds for each drive in both modes,
> >3 dds per drive is enough to cause "Queue Full" in both modes, but
> >it is harmless due to read only.
> 
> This is probably what is causing your corruption in the SCB Paging case.
> Which drive can only do 3 transactions at a time?  I'm sure that your IBM
> can do more.  It may very well be that one of your drives doesn't like the
> fact that the code with SCB paging turned on will basically continually
> pound on that drive, causing queue full conditions, until there aren't
> enough transactions queued to make this happen any more.  The patch I
> posted for Andreas' problem may help in this regard.

No, _any_ of two
drives says "Queue full" after 2-3 dds and goes to "timed out" state
after more dds which ends up with "panic: Timed-out command times out again"
It happens equally in both SCB paging and not SCB paging modes.
BTW, I see it only for dds, I can start f.e. about 20 "ls -lR" safely.

Does it means that Tagged Queueing not work well with 2842?

> As for your problem happening on the "first write", are you sure this isn't
> the "first sync" after boot??

I mean first physical write, of course. It happens just after
fsck puts info lines about each drive at boot phase.

-- 
Andrey A. Chernov
<ache@nagual.ru>
http://www.nagual.ru/~ache/



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199611132213.BAA00212>