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Date: Tue, 22 Jul 2014 11:22:07 -0600 (MDT)
From: Warren Block <wblock@wonkity.com>
To: Polytropon <freebsd@edvax.de>
Subject: Re: How much swap space for a 32 GB RAM system?
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Cc: Arthur Chance <freebsd@qeng-ho.org>,
 FreeBSD-Questions <freebsd-questions@freebsd.org>
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On Tue, 22 Jul 2014, Polytropon wrote:

> On Tue, 22 Jul 2014 17:05:12 +0100, Arthur Chance wrote:
>> I'm getting a new machine with 32 GB of memory. The old "twice physical
>> memory" sizing seems ridiculous, so how big should I make swap? Do I
>> even need swap with this much memory?
>
> Need? Probably not, but you _never_ know... So preparing
> a file-backed swap could be a nice solution: you do not
> have to dedicate a fixed size partition for swap, and
> depending on your disk setup (maybe SSD?) the speed (_if_
> it gets in use) will be good enough. In order to do this,
> you use dd to create a sparse file,

File yes, sparse file no.  Bad Things(TM) may happen with a sparse file.

> configure it as a
> memory disk, and enable it with swapctl.

In 10.x, this can be done in /etc/fstab.