SUMMARY: swapfile vs swap partitions

From: Dave Hightower (hightowr@afwc.af.mil)
Date: Tue Apr 18 1995 - 00:57:30 CDT


Well, the consensus was that using a swapfile as opposed to
a swap partition is slower, mainly because you have to go through
the filesystem and OS, whereas a swap partition uses a straight
dump to the drive.

Some people also warned about disk fragmentation, and how that
would slow down the swapping; the swap partition will obviously
always be contiguous.

Using a swapfile is suggested in those instances when your users
are running temporary memory-intensive applications, or as an
interim measure when you upgrade a system's memory (until you can
repartition the drive).

Thanks to:

        Kevin.Sheehan@uniq.com.au (Kevin Sheehan {Consulting Poster Child})
        gaskell@chester.digicon-egr.co.uk (Phil Gaskell)
        okenka@garnet.msen.com (Kenneth P. Okenka)
        gdonl@gv.ssi1.com (Don Lewis)
        Boyd Fletcher <boyd@ccpo.odu.edu>
        poffen@San-Jose.ate.slb.com (Russ Poffenberger)
        jmarble@cambric.com (Jeff Marble)
        Reto Lichtensteiger <rali@hri.com>
        Paul Caskey <pcaskey@swcp.com>
        dhoward@worldlinx.com
        Bruce Skidmore <skidmorb@ochampus.mil>
        Nate Itkin <Nate-Itkin@ptdcs2.intel.com>
        Dan Stromberg - OAC-CSG <strombrg@hydra.acs.uci.edu>
        "Lau, Victoria H" <vlau@msmail2.hac.com>
        Glenn.Satchell@uniq.com.au (Glenn Satchell - Uniq Professional Services)
        David Lee <T.D.Lee@durham.ac.uk>
        lucas@blucas.nadn.navy.mil (Bonnie Lucas)
        Kai Grossjohann <grossjoh@groucho.informatik.uni-dortmund.de>

The original question:

> Some things that I have read indicate that some locations are using a
> swapfile instead of a "swap partition" to better control the size and
> location of their swap space.
>
> Currently we use the "b" partition of our boot hard drive for swap space,
> and we size it to be twice the size of our physical memory. This creates
> a problem when we increase the memory in our systems, as we are then
> required to reformat and repartition.
>
> So the question becomes: Is there any performance information comparing
> an actual "swap partition" to a swapfile? is one faster than the other?
> Would performance suffer were we to use a swapfile instead?

Dave
______________________________________________________________________________
Dave Hightower | opinion? I'm allowed to have an opinion?
Systems Manager | well, if I DID have one, it'd be mine, all mine!
Air Force Wargaming Center | "Dum vivimus, vivamus!"
hightower@afwc.af.mil |
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