From owner-freebsd-fs@FreeBSD.ORG Sun Oct 2 15:11:47 2011 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4C745106564A; Sun, 2 Oct 2011 15:11:47 +0000 (UTC) (envelope-from delphij@delphij.net) Received: from anubis.delphij.net (anubis.delphij.net [IPv6:2001:470:1:117::25]) by mx1.freebsd.org (Postfix) with ESMTP id 2BD518FC08; Sun, 2 Oct 2011 15:11:47 +0000 (UTC) Received: from delta.delphij.net (c-76-102-50-245.hsd1.ca.comcast.net [76.102.50.245]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by anubis.delphij.net (Postfix) with ESMTPSA id D377415690; Sun, 2 Oct 2011 08:11:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=delphij.net; s=anubis; t=1317568307; bh=nbvKB1cH4w8CwhhWcC1oR6PC1bIV0/sk9AV5C8JMGdM=; h=Message-ID:Date:From:Reply-To:MIME-Version:To:CC:Subject: References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=HxNC+HreYOYtfspMh6jNJ7kB2C1UbZmdWMJrTol2GNzsMRQHZ5qiaeq/aAY4MqltF 8Y8R+U30982FZEVtTY/olofWtu3SL327CdWoqvqy3xAknpWpltdhmS82HOGMrAvtI2 iScU8sGC0sRnUKcqyud/WDNUX3GXaXHF2pRtE8Jc= Message-ID: <4E887F31.8000407@delphij.net> Date: Sun, 02 Oct 2011 08:11:45 -0700 From: Xin LI Organization: The FreeBSD Project MIME-Version: 1.0 To: Olivier Smedts References: In-Reply-To: OpenPGP: id=3FCA37C1; url=http://www.delphij.net/delphij.asc Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org, Adrian Chadd , delphij@freebsd.org Subject: Re: is TMPFS still highly experimental? X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: d@delphij.net List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 02 Oct 2011 15:11:47 -0000 -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 On 10/02/11 03:23, Olivier Smedts wrote: > 2011/10/2 Xin LI : >> Hi, >> >> On Sat, Oct 1, 2011 at 8:48 AM, Chris Rees >> wrote: >>> I've also not heard of anyone using it with zfs successfully- >>> it tends to shrink rapidly. >> >> I'm quite surprised with this assertion. I use tmpfs on my own >> system and I never see such problem as long as one have >> sufficient swap space. > > The problem here is "sufficient swap space". > > I've got 8G of RAM, and 2G of swap (just in case). When the ZFS > ARC reaches 4G, there's no room for a single byte in tmpfs, even > with 2G swap free and at least 2-3G RAM free. The swap size must be > at least the RAM size if you plan on using ZFS and tmpfs. That's a > problem for me because I'm short on disk space, and there's no > point in having an enormous swap size (hey, minidumps !) when you > already have lots of RAM, which is the case in most ZFS installs. A possible workaround for this might be limiting ARC size? I can't think about any better idea at this point. My personal experience is always have at least RAM sized swap because the system may choose to write in-core data to swap which enables it to discard these memory without expensive swapout in emergency cases. Depending on workload, this could give better responsiveness and frankly I never consider having a few tens of GBs of swap as expensive since large disks are not expensive nowadays... Cheers, - -- Xin LI https://www.delphij.net/ FreeBSD - The Power to Serve! Live free or die -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iQEcBAEBCAAGBQJOiH8xAAoJEATO+BI/yjfB/BsH/1IpXJioC+R5ZwUBE2mRDP/E rlwGjx138iHFzUjQn7Q8YYmmPhUKiad2fQOIwnErfMOjPUiEVP/CLBya6jQG8g6n wHco8ilIerMSM8i7R1iTbC9gJxte2orxTBrnLkTMr1AcW/MjxpSBL4Z2kzIrZdsx 8bEFCig0tKY5gluM8ZTBaMK+yVEFV+ff6PHiHu//XcnG03CFqiu9V4HMhvrXCTcB QBDl+/8+PdLPWEDHLzSW51te1YEoF/xDkDkHu7UtTX3egEkiDeZ2uCmazgWFu/Xw TPMRiXUfYklDpT+rMbRH44CN5VeEWhOyZRDyr/pGOzjylAe2ShFGNxpua+KpLJI= =0mDY -----END PGP SIGNATURE-----