Date: Thu, 24 May 2001 02:10:01 -0700 (PDT) From: Stefan `Sec` Zehl <sec@42.org> To: freebsd-doc@freebsd.org Subject: Re: docs/27599: md(4) manpage enhancement Message-ID: <200105240910.f4O9A1B51335@freefall.freebsd.org>
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The following reply was made to PR docs/27599; it has been noted by GNATS.
From: Stefan `Sec` Zehl <sec@42.org>
To: Dima Dorfman <dima@unixfreak.org>
Cc: FreeBSD-gnats-submit@freebsd.org
Subject: Re: docs/27599: md(4) manpage enhancement
Date: Thu, 24 May 2001 11:00:50 +0200
On Wed, May 23, 2001 at 08:57:23PM -0700, Dima Dorfman wrote:
> sec@ice.42.org writes:
> > --- /usr/export/src/share/man/man4/md.4 Sun Dec 31 03:11:56 2000
> > +++ ./md.4 Thu May 24 00:56:57 2001
> > @@ -59,6 +59,11 @@
> > with the kernel option
> > .Dv MD_NSECT .
> > .Pp
> > +Be warned that due to kernel constraints such a
> > +.Nm
> > +disk cannot be bigger than a certain maximum size.
> > +This size can be found in the 'Limit' column of 'vmstat -m'.
> > +.Pp
>
> It looks to me like the man page already states this:
>
> The default maximum size of a md disk backed by malloc(9) is 20,000 sec-
> tors of 512 bytes each. This can be changed with the kernel option
> MD_NSECT.
>
> Perhaps it might make sense to mention vmstat(8), but I don't think
> it's appropriate to add another paragraph, most of which just repeats
> what has already been said.
I'm sorry, but you misunderstand. The problem I mention has nothing to
do with MD_NSECT. You can raise MD_NSECT all the way, but the mentioned
'Limit' column of 'vmstat -m' Is unaffected by that. That is exactly
where this comes from. The default MD_NSECT is small enough to avoid any
problems, but when you increase it, you run into that other, not yet
documented limit which will HANG your machine.
If my english isn't clear enough, feel free to improve it. But please
add a warning to the manpage.
CU,
Sec
--
There are too many priorities. One has to prioritize priorities. -- Wietse
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