From owner-freebsd-stable@FreeBSD.ORG Thu Nov 29 21:31:32 2012 Return-Path: Delivered-To: freebsd-stable@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id A6A86322 for ; Thu, 29 Nov 2012 21:31:32 +0000 (UTC) (envelope-from avg@FreeBSD.org) Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140]) by mx1.freebsd.org (Postfix) with ESMTP id EAEB98FC12 for ; Thu, 29 Nov 2012 21:31:31 +0000 (UTC) Received: from porto.starpoint.kiev.ua (porto-e.starpoint.kiev.ua [212.40.38.100]) by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id XAA14406; Thu, 29 Nov 2012 23:31:28 +0200 (EET) (envelope-from avg@FreeBSD.org) Received: from localhost ([127.0.0.1]) by porto.starpoint.kiev.ua with esmtp (Exim 4.34 (FreeBSD)) id 1TeBhg-0001iN-GG; Thu, 29 Nov 2012 23:31:28 +0200 Message-ID: <50B7D42E.9010904@FreeBSD.org> Date: Thu, 29 Nov 2012 23:31:26 +0200 From: Andriy Gapon User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Nikolay Denev Subject: Re: ZFS memory management References: <7A88B836-C985-446C-A992-A295A2474A38@gmail.com> In-Reply-To: X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-stable@FreeBSD.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 29 Nov 2012 21:31:32 -0000 on 29/11/2012 19:16 Nikolay Denev said the following: > > On Nov 29, 2012, at 4:53 PM, Olivier Smedts wrote: > >> 2012/11/27 Freddie Cash : >>> Read any ZFS tuning manual on the web, including the ones direct from >>> SUN/Oracle, and they all list: >>> - if you are running processes that need a lot of memory, then limit the >>> ARC to allow the apps to have access to that memory >> >> Or you could have at least a little swap (good practice) to allow ARC >> take the time to evict some memory when under pressure. >> > > Yes, this was already suggested off-list, and it seems like a solution. > > Thanks to all for the input! I think that various VM thresholds are not very well auto-tuned for a swap-less system. So, perhaps, something to _experiment_ with... I could make sense to increase (e.g. double or triple) vm.v_cache_min, so that the pager is waken up earlier. At the same time vm.v_free_target could be decreased so that difference between it and vm.v_free_reserved is smaller (but greater than zero). My understanding is that OOM handling is activated when the pager can not get number of available (free + cached) pages above v_cache_min + v_free_target after two passes. -- Andriy Gapon