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From: "John Levine" <johnl@iecc.com>
To: freebsd-questions@freebsd.org
Cc: kremels@kreme.com
Subject: Re: Swap on SSD
In-Reply-To: <99D367C9-ADF4-41EB-8D4F-5D5F3B0C7ABF@kreme.com>
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In article <99D367C9-ADF4-41EB-8D4F-5D5F3B0C7ABF@kreme.com> you write:
>>> Should the installer then be creating a dedicated swap partition? It
>>> seems not.
>> 
>> 	Yes of course it should, it's the place where pages that aren't
>> backed by storage can be written to when needed.
>
>That seems easily solved (just as well) by a swapfile.

FreeBSD lets you have either or both, but a swap partition is faster.

If you use a swap partition, block N is at disk location B+N where B
is the base of the partition.  If you use a swapfile, you have inodes
and indirect blocks and such, so random access to a large swapfile
might have to read one or two overhead blocks for every swap block.