From owner-freebsd-stable@FreeBSD.ORG Fri Feb 12 23:47:13 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2515D106568D for ; Fri, 12 Feb 2010 23:47:13 +0000 (UTC) (envelope-from korvus@comcast.net) 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 C4BF88FC13 for ; Fri, 12 Feb 2010 23:47:12 +0000 (UTC) Received: from omta12.westchester.pa.mail.comcast.net ([76.96.62.44]) by qmta03.westchester.pa.mail.comcast.net with comcast id h0Wx1d0020xGWP853BmgP9; Fri, 12 Feb 2010 23:46:40 +0000 Received: from [10.0.0.51] ([71.199.122.142]) by omta12.westchester.pa.mail.comcast.net with comcast id hBnC1d00534Sj4f3YBnCh7; Fri, 12 Feb 2010 23:47:13 +0000 Message-ID: <4B75E88A.1050300@comcast.net> Date: Fri, 12 Feb 2010 18:47:22 -0500 From: Steve Polyack User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-GB; rv:1.9.1.7) Gecko/20100111 Lightning/1.0b1 Thunderbird/3.0.1 MIME-Version: 1.0 To: Artem Belevich References: <4B759E70.4030809@comcast.net> <4B75ADC7.6000308@comcast.net> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org, freebsd-stable Subject: Re: ZFS ARC being limited below what is defined in /boot/loader.conf X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Feb 2010 23:47:13 -0000 This was indeed the issue. I read your first response incorrectly. Thanks a bunch! On 2/12/2010 4:10 PM, Artem Belevich wrote: > vm.kmem_size_max/vm.kmem_size_min define the range vm.kmem_size can be set to. > vm_kmem_size specifies the actual kmem size. > > ARC size in turn limited by vm.kmem_size. > > If you want to bump ARC size, you do need to bump vm.kmem_size. > > --Artem > > > > On Fri, Feb 12, 2010 at 11:36 AM, Steve Polyack wrote: > >> On 02/12/10 13:47, Artem Belevich wrote: >> >>> On Fri, Feb 12, 2010 at 10:31 AM, Steve Polyack >>> wrote: >>> >>> >>> >>>> Has anyone had an issue with the ZFS ARC max being limited below what has >>>> been defined in /boot/loader.conf? I just upgraded the RAM in a >>>> ZFS-equipped system and attempted to devote 4GB to the ARC cache by >>>> placing >>>> the following in loader.conf: >>>> vfs.zfs.arc_max="4096M" >>>> >>>> However, after rebooting, querying the sysctl gives me this: >>>> $ sysctl vfs.zfs.arc_max >>>> vfs.zfs.arc_max: 1726489600 >>>> >>>> or about 1.7GB, an odd number that I can't find any references to. For >>>> reference, I'm running 8-STABLE (as of Jan 19th) on an amd64 system with >>>> 8GB >>>> of RAM. The system was previously very stable with 4GB of RAM and a >>>> 512MB >>>> arc_max. I have not modified vm.kmem_size_max (defaults to ~330GB on >>>> amd64) >>>> or any other ZFS tunables. I'd also like to avoid syncing up to the >>>> current >>>> 8-STABLE if at all possible. >>>> >>>> Thanks, >>>> Steve Polyack >>>> >>>> _______________________________________________ >>>> freebsd-stable@freebsd.org mailing list >>>> http://lists.freebsd.org/mailman/listinfo/freebsd-stable >>>> To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >>>> >>>> >>>> >>> Check your vm.kmem_size. Default setting is way too low. Set it to at >>> least double of desired arc size. >>> >>> --Artem >>> >> I mentioned it briefly, but vm.kmem_size_max was left at the default for >> amd64. At 330GB it is way above and beyond what will ever be allocated to >> ARC: >> $ sysctl vm.kmem_size_max >> vm.kmem_size_max: 329853485875 >> >> >> >> >