From owner-freebsd-current@FreeBSD.ORG Wed Nov 19 10:13:48 2008 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A9F631065701 for ; Wed, 19 Nov 2008 10:13:48 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from QMTA03.westchester.pa.mail.comcast.net (qmta03.westchester.pa.mail.comcast.net [76.96.62.32]) by mx1.freebsd.org (Postfix) with ESMTP id 4DD398FC12 for ; Wed, 19 Nov 2008 10:13:48 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from OMTA06.westchester.pa.mail.comcast.net ([76.96.62.51]) by QMTA03.westchester.pa.mail.comcast.net with comcast id gy4P1a00316LCl053yCpen; Wed, 19 Nov 2008 10:12:49 +0000 Received: from koitsu.dyndns.org ([69.181.141.110]) by OMTA06.westchester.pa.mail.comcast.net with comcast id gyDm1a00L2P6wsM3SyDnhr; Wed, 19 Nov 2008 10:13:47 +0000 X-Authority-Analysis: v=1.0 c=1 a=UoFpbzuMWasA:10 a=6VqBrpBaAAAA:8 a=QycZ5dHgAAAA:8 a=oydLpk_76dDEq0tLX_4A:9 a=RkjAjTsfDuh_-YXShVIA:7 a=jMdACBzFH7T3uMEgSFKaEp4IR_EA:4 a=DC3OrDK0E1IA:10 a=EoioJ0NPDVgA:10 a=h-mJ8WrWerMA:10 a=LY0hPdMaydYA:10 Received: by icarus.home.lan (Postfix, from userid 1000) id 9105C33C36; Wed, 19 Nov 2008 02:13:46 -0800 (PST) Date: Wed, 19 Nov 2008 02:13:46 -0800 From: Jeremy Chadwick To: Nikolay Denev Message-ID: <20081119101346.GA82818@icarus.home.lan> References: <20081117205526.GC1733@garage.freebsd.pl> <8ECD400F-BFE3-4E31-94F0-39AF5F44FDAC@gmail.com> <20081119090307.GA81236@icarus.home.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Cc: freebsd-current@freebsd.org, Larry Rosenman Subject: Re: HEADS UP: New ZFS in the tree. X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Nov 2008 10:13:48 -0000 On Wed, Nov 19, 2008 at 11:48:17AM +0200, Nikolay Denev wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > > On 19 Nov, 2008, at 11:25 , Larry Rosenman wrote: > >> On Wed, 19 Nov 2008, Jeremy Chadwick wrote: >> >>> >>> Since this is CURRENT, you should be able to increase the kmem_size >>> and kmem_size_max entries to something larger than 1536M, especially >>> since the box has 4GB of RAM. (You shouldn't do this on RELENG_7). >>> >>> You might also consider disabling prefetch; there are reports of >>> peoples' boxes locking up hard (requiring a hard reset) when prefetch >>> is enabled. Others (like myself) just see "better overall system >>> responsiveness" when prefetch is disabled. >> Just as a note, with a -CURRENT from shortly after the ZFS upgrade, >> the vm.kmem* tuneables, without ANY override on my 4G amd64 box: >> >> vm.kmem_size_scale: 3 >> vm.kmem_size_max: 4509713203 >> vm.kmem_size_min: 0 >> vm.kmem_size: 1381195776 >> >> this is with a 2T zfs array, if that matters. >> >> >> -- >> Larry Rosenman http://www.lerctr.org/~ler >> Phone: +1 512-248-2683 E-Mail: ler@lerctr.org >> US Mail: 430 Valona Loop, Round Rock, TX 78681-3893 > > Well, it looks like that on -current and a 4G amd64 machine probably > there is no need > to tune anything. Here are my defaults with everything vm and zfs > related in loader.conf commented : > > vm.kmem_size_max: 4509713203 > vfs.zfs.arc_max: 863907840 I've discussed ZFS tuning with another FreeBSD user 2-3 months ago. I lost 8 years worth of Email recently, so I can't go back and check who he was and what exactly was said. He was saying that under normal circumstances (in RELENG_7 and CURRENT), tuning should not really be necessary. He also pointed out that the way we're tuning things (specifically the variables we're using) are partially incorrect; some are unnecessary, such as arc_min. I'll see if I can find the mail on a mailing list (I think it was a public mail), but it'll take me some time. The information in the mail is very good, and should probably be pulled in to the ZFS Tuning wiki. Give me a while to find it. -- | Jeremy Chadwick jdc at parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |