Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 11 Dec 2017 07:56:55 +0000
From:      Matthew Seaman <matthew@FreeBSD.org>
To:        freebsd-questions@freebsd.org
Subject:   Re: Subject: Thunderbird causing system crash, need guidance
Message-ID:  <460ae512-89b6-d09f-b567-fefff373b087@FreeBSD.org>
In-Reply-To: <38e2ef70-fa1b-25bf-4447-752006418d0a@dreamchaser.org>
References:  <201712110045.vBB0jCTQ078476@nightmare.dreamchaser.org> <CA+tpaK0sG31TckxL8orNmAD0ZXSz7rJzEotjsCEtASw9u2COZg@mail.gmail.com> <38e2ef70-fa1b-25bf-4447-752006418d0a@dreamchaser.org>

Next in thread | Previous in thread | Raw E-Mail | Index | Archive | Help
This is an OpenPGP/MIME signed message (RFC 4880 and 3156)
--AFBwo7wp1gqfvdE9PqmhbChwhLs1KGw3r
Content-Type: multipart/mixed; boundary="AiAnrERI51btcvqg2w9rKEb5eeCHDaqxf";
 protected-headers="v1"
From: Matthew Seaman <matthew@FreeBSD.org>
To: freebsd-questions@freebsd.org
Message-ID: <460ae512-89b6-d09f-b567-fefff373b087@FreeBSD.org>
Subject: Re: Subject: Thunderbird causing system crash, need guidance
References: <201712110045.vBB0jCTQ078476@nightmare.dreamchaser.org>
 <CA+tpaK0sG31TckxL8orNmAD0ZXSz7rJzEotjsCEtASw9u2COZg@mail.gmail.com>
 <38e2ef70-fa1b-25bf-4447-752006418d0a@dreamchaser.org>
In-Reply-To: <38e2ef70-fa1b-25bf-4447-752006418d0a@dreamchaser.org>

--AiAnrERI51btcvqg2w9rKEb5eeCHDaqxf
Content-Type: text/plain; charset=utf-8
Content-Language: en-GB
Content-Transfer-Encoding: quoted-printable

On 11/12/2017 04:56, Gary Aitken wrote:

>>> md99                  none  swap    sw,file=3D/usr/swap/swap,late
0       0

>> Your swap configuration is also mostly likely silly.=C2=A0 If you need=

>> more performance, that's not the way to do it.

> Can you explain or point me to an explanation for this comment?=C2=A0 I=
t
> looks to me like what's shown in the EXAMPLES section of "man fstab".

You're swapping to a file-backed memory device, which is not the best
choice for performance.  The best choice is to swap to raw partitions on
your hard drives.  Having several disks with a swap partition on each
can help, as it allows you to spread the IO load over several devices,
but that's a marginal gain and not necessary in general.

The reasoning being that you're involving all of the kernel machinery to
support filesystem IO for what is meant to be the very low-level and
simplified operation of paging memory in and out of swap.

Yes, you can create a file-backed swap area, but just because you can
doesn't mean you should.  Creating a file-backed swap is useful in
special cases, like you're working on that part of the kernel and need
to test adding or removing swap devices, or you're trying to cope with
some exceptional process that is really far too large for your system to
handle.

Ideally nowadays you should have enough RAM to contain all of your
active processes without needing to swap, so the whole point should
really be moot.

	Cheers,

	Matthew





--AiAnrERI51btcvqg2w9rKEb5eeCHDaqxf--

--AFBwo7wp1gqfvdE9PqmhbChwhLs1KGw3r
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: OpenPGP digital signature
Content-Disposition: attachment; filename="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=13fl
-----END PGP SIGNATURE-----

--AFBwo7wp1gqfvdE9PqmhbChwhLs1KGw3r--



Want to link to this message? Use this URL: <http://docs.FreeBSD.org/cgi/mid.cgi?460ae512-89b6-d09f-b567-fefff373b087>