Re: Raw-io & Swap partitions

Andrzej Krzysztofowicz (ankry@oberon.idk.com.pl)
Tue, 22 Dec 1998 13:22:41 +0100 (MET)

Peter Waltenberg <peterw@dascom.com> wrote
> Assuming there's little performance difference between swap
> partitions and swap files, swap files are a big win. No hardwired
> decision on how much swap is needed, just create a swap file
> in one of the filesystems. If you find it's too big or too small it
> can be resized easilly. (Unlike a partition).
>
> On the flip side, if swap partitions do give some advantages, surely
> the same justification can be made for supporting raw-io.

Using swapfiles is still not so safe as swap partitions. Eg.:

# dd if=/dev/zero of=s1 bs=8192 count=1024
# ln s1 s2
# ls -l s*
-rw-r--r-- 2 ankry staff 8388608 Dec 22 13:16 s1
-rw-r--r-- 2 ankry staff 8388608 Dec 22 13:16 s2
# mkswap s1
Setting up swapspace, size = 8384512 bytes
# swapon s1
# swapon s2
###### ^^^ !!!!!!!!!!!!!!!! works !!!!!!!!

# cat /proc/swaps
Filename Type Size Used Priority
/tmp/s1 file 8188 0 -1
/tmp/s2 file 8188 0 -2

You can double swapspace in the *same* file !
2.1.131
I think it's also possible with 2.0...

--
=======================================================================
  Andrzej M. Krzysztofowicz               ankry@mif.pg.gda.pl
  phone: (48)(58) 347 14 61            fax: (48)(58) 347 28 21
Faculty of Applied Phys.& Maths, Technical University of Gdansk, Poland


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