From owner-freebsd-questions@freebsd.org Mon Dec 11 07:57:01 2017 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2C1BBE8919B for ; Mon, 11 Dec 2017 07:57:01 +0000 (UTC) (envelope-from matthew@FreeBSD.org) Received: from smtp.infracaninophile.co.uk (smtp.infracaninophile.co.uk [81.2.117.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "smtp.infracaninophile.co.uk", Issuer "infracaninophile.co.uk" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id B0B2876105 for ; Mon, 11 Dec 2017 07:57:00 +0000 (UTC) (envelope-from matthew@FreeBSD.org) Received: from liminal.local (unknown [IPv6:2001:8b0:151:1:9987:5863:73dd:de7d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: m.seaman@infracaninophile.co.uk) by smtp.infracaninophile.co.uk (Postfix) with ESMTPSA id 810BAD8E8 for ; Mon, 11 Dec 2017 07:56:56 +0000 (UTC) Authentication-Results: smtp.infracaninophile.co.uk; dmarc=none (p=none dis=none) header.from=FreeBSD.org Subject: Re: Subject: Thunderbird causing system crash, need guidance To: freebsd-questions@freebsd.org References: <201712110045.vBB0jCTQ078476@nightmare.dreamchaser.org> <38e2ef70-fa1b-25bf-4447-752006418d0a@dreamchaser.org> From: Matthew Seaman Message-ID: <460ae512-89b6-d09f-b567-fefff373b087@FreeBSD.org> Date: Mon, 11 Dec 2017 07:56:55 +0000 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: <38e2ef70-fa1b-25bf-4447-752006418d0a@dreamchaser.org> Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="AFBwo7wp1gqfvdE9PqmhbChwhLs1KGw3r" X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 11 Dec 2017 07:57:01 -0000 This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --AFBwo7wp1gqfvdE9PqmhbChwhLs1KGw3r Content-Type: multipart/mixed; boundary="AiAnrERI51btcvqg2w9rKEb5eeCHDaqxf"; protected-headers="v1" From: Matthew Seaman 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> <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----- iQKoBAEBCgCSFiEEGfFU7L8RLlBUTj8wAFE/EOCp5OcFAlouOkhfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldDE5 RjE1NEVDQkYxMTJFNTA1NDRFM0YzMDAwNTEzRjEwRTBBOUU0RTcUHG1hdHRoZXdA ZnJlZWJzZC5vcmcACgkQAFE/EOCp5OfF8xAAo1+E1uibv0ykffE3kFXHXq6FyO5+ QTvn2A78c3IHCgUjIH/UvHZfjFWQzgSTUVCjPLI20TWhtIs0QqUXkkFPkYveZQur xrq6ztKKy3XmbCS4VuURNRSYlQ8Ii/HFeysPr3NaCxenxc2ZcdhbG5xwAnJ68HgF J1AjEiYGrd/UCHg+asUouNly7BPAjmyTQ0B1c2HXH1rHJWT/Ub81IkJVN0z1NCaA od84W/f9n/PrwTTfla9sHdTtNrXRQhx/jmMuG0Dy2hA3f4w6RYsEiC7nrw0M1LBp WCF7FohP5c7gSHndz3+/R83pmoW+aOVBjLovt5LtVRw4xBrJZBafeUHPyTnBW0aT NgCLh1oPCNAJ/EC5Ah4SB/Mw44yELXyBu/yr0n+4F1cwYWZIIB5Qg48/R4+YLHl3 6EH403Dj7/1RNgQuH41CfOJNfC6u/rPNoeuljdJoP8N+cOv1TY7FK1NmqxDLKwGH 8CBhtDvQUM3MtKUP7zDZzjzxWMfOodSoLkXdmysPc8jAHC01xgyUiCcfmGquL6en 4BOHNQQKarRexfMySN4rXioIGYbMbNapdYfkpMBnLfRGyoIrfzke8b8B7dgX7cbq dluog6cM+V+9xPVpQ06nmp0gT6c+kl6JiC4yT+lMDpv4EmSa1LTYQNhTHYpv0c6t 9ANKPAp6whCOOCA= =13fl -----END PGP SIGNATURE----- --AFBwo7wp1gqfvdE9PqmhbChwhLs1KGw3r--