From owner-freebsd-current@FreeBSD.ORG Thu Apr 29 18:25:55 2010 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 B69C6106566B for ; Thu, 29 Apr 2010 18:25:55 +0000 (UTC) (envelope-from artemb@gmail.com) Received: from mail-pz0-f201.google.com (mail-pz0-f201.google.com [209.85.222.201]) by mx1.freebsd.org (Postfix) with ESMTP id 8537A8FC08 for ; Thu, 29 Apr 2010 18:25:55 +0000 (UTC) Received: by pzk39 with SMTP id 39so3122807pzk.7 for ; Thu, 29 Apr 2010 11:25:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:sender:received :in-reply-to:references:date:x-google-sender-auth:message-id:subject :from:to:cc:content-type:content-transfer-encoding; bh=lC1IfH+hLAZW8Ifn7G7LAsGxq4D8vQmM+DbAPGMSq2s=; b=ThsdU+m44EqIK7JY0ej/ExX4Jnn2pY4Ix3qDbMIQurO1mMY56Ye7y+1oRAnzw2KOIC lbYqoxlSrX4lHOIzr+Y0eJNvUZLkr+1TW1pPhZAADnBC0xg1b6Ccmac0Lhka42sSMbop SHImqD68wk7hyY9H4d0uHhfvCBuzBiUteiGgo= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=QlVal1bVO3gLC2BJg8NTk7gKsPbOF9ToHAnZi27x18zRN/RGVaWOI/fJJi2TXXg2Ik pJ741CV/kpiJ5T1HaTZ0PFF7nP4j+iVzdaIisaXV6AgD7DRDnyiR9BTjKXznbqNM0oND DzWBSIS0i1i1C9OFzNTk8Ssy+9s+NKN/GrC70= MIME-Version: 1.0 Received: by 10.140.248.18 with SMTP id v18mr5588775rvh.295.1272565547320; Thu, 29 Apr 2010 11:25:47 -0700 (PDT) Sender: artemb@gmail.com Received: by 10.141.29.10 with HTTP; Thu, 29 Apr 2010 11:25:46 -0700 (PDT) In-Reply-To: References: <4BD8F7FA.2080103@jrv.org> <20100429145334.GB62822@roberto-al.eurocontrol.fr> Date: Thu, 29 Apr 2010 11:25:46 -0700 X-Google-Sender-Auth: 8b304f03eebd6b5b Message-ID: From: Artem Belevich To: Scott Long Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: Tom Evans , Ollivier Robert , freebsd-current@freebsd.org Subject: Re: kmem_map too small: 3832475648 total allocated 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: Thu, 29 Apr 2010 18:25:55 -0000 If I understand it correctly, the problem in this case is that even when you do have more than enough RAM, kernel just does not provide enough space in kmem_map to map that physical memory into. Unless you want to have dedupe turned on large filesystem (and FreeBSD does not have this feature yet), you don't really *need* all that much RAM. "kmem_map too small" comes up as an issue way more often than lack of physical memory. --Artem On Thu, Apr 29, 2010 at 9:56 AM, Scott Long wrote: > On Apr 29, 2010, at 9:44 AM, Tom Evans wrote: >> On Thu, Apr 29, 2010 at 3:53 PM, Ollivier Robert >> wrote: >>> According to James R. Van Artsdalen: >>>> system is a Core i7 975 (3.33 GHz x 4 cores 3x threads per core) with = 12 >>>> GB of RAM, a 2x2TB ZFS boot pool and a second (idle) pool of 16x2TB. >>> >>>> panic: kmem_malloc(131072): kmem_map too small: 3832475648 total alloc= ated >>> >>> Apart from the fact that you must at least set vm.kmem_size to somethin= g like 2x your RAM, one rule of thumb I've seen discussed for ZFS is that y= ou will need approximatively 1 GB of RAM per TB of data so you may be a bit= short here to get optimal perfs. >>> >> >> Citation needed? I have a file server running amd64 8-STABLE with 4GB >> of RAM, 6 x 1.5 TB drives in raidz, and have never had any problems >> with memory usage. Are you saying that after my next update, adding >> another 6 x 1.5 TB drives, it will start being flaky and/or panicing >> with kmem_map too small errors? >> > > I'm sorry, but I find it absolutely absurd that any filesystem has to wir= e down 2GB of RAM, and that the solution to panics is buy more RAM. > > Scott > > _______________________________________________ > freebsd-current@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-current > To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org= " >