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Date: Fri, 1 Aug 2003 09:51:50 -0700
From: David Schultz <das@freebsd.org>
To: Poul-Henning Kamp <phk@phk.freebsd.dk>
Message-ID: <20030801165150.GA78091@HAL9000.homeunix.com>
Mail-Followup-To: Poul-Henning Kamp <phk@phk.freebsd.dk>,
	Adrian Chadd <adrian@freebsd.org>, arch@freebsd.org
References: <20030801083628.GB56492@skywalker.creative.net.au>
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cc: arch@freebsd.org
Subject: Re: headsup: swap_pager.c
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On Fri, Aug 01, 2003, Poul-Henning Kamp wrote:
> In message <20030801083628.GB56492@skywalker.creative.net.au>, Adrian Chadd wri
> tes:
> >On Fri, Aug 01, 2003, Poul-Henning Kamp wrote:
> >
> >> >Can you please describe how the interface between ccd(4) and the
> >> >swap subsystem will work?  I like this idea, but it isn't
> >> >immediately obvious how you plan to implement striping based on
> >> >load and dynamic addition and removal of swap space.
> >> 
> >> 	ccdconfig -c ccd0 128 0 /dev/da0b /dev/da1b /dev/da2b
> >> 	swapon /dev/ccd0
> >
> >.. and if I want to add another swap device, will that work?
> 
> Yes, but it will of course not be striped with the rest, it will
> be laid out sequentially.
> 
> And as a side effect you will not run into the NSWAP=4 limitation
> any more.

Aah, okay.  That's both a small improvement and a small regression
in one.  The point of the static striping was to allow you to add
swap devices and have them be automatically interleaved, so of
course you can ``fix'' its limitations by removing it completely.

I was kinda hoping you had a more flexible (albeit complex) plan
in mind that would allow swap space to be striped on the fly based
on disk load, free space on each disk, etc.