From owner-freebsd-fs@FreeBSD.ORG Fri Mar 4 10:56:22 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 B919710656B9 for ; Fri, 4 Mar 2011 10:56:22 +0000 (UTC) (envelope-from mgamsjager@gmail.com) Received: from mail-gw0-f44.google.com (mail-gw0-f44.google.com [74.125.83.44]) by mx1.freebsd.org (Postfix) with ESMTP id 71E178FC0C for ; Fri, 4 Mar 2011 10:56:22 +0000 (UTC) Received: by gwaa18 with SMTP id a18so1679012gwa.17 for ; Fri, 04 Mar 2011 02:56:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-type; bh=Wqm2Bp5hoyYc9TJE8yPdOqJ0sfFTMezWKxVOpWZac8w=; b=KYPiT/kS8ouPoIUKLhucEj0v45O5HX0ppk0E8KtGFoof+YXrSOLrRJQJqjQ5PrZUMd x16ZfeEDExglwS6jBnyKV00nFJ1HUBztb/RN+a4wxYOhjTUyP86G55u5zrQBpvOPRW1c SfpLxLmiEORfBQS6n3rn8wQCDYJ8P8mRwBCD8= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; b=Dt2ffDmlEk6ppzny0okPh5o4WiHaI2sjCR0ehlNFwJoQEt23li4vR5Ia5mRH9Zp+00 9PoGE1EreNXoraBxV6gs3dsCkobhofuixHs2Up71ATmOw9NmbHJn1yFui0jaPihbum0q jakTisP21Vmi+ZchtwTs2ZCmCXSplKuH4N7LM= Received: by 10.100.195.5 with SMTP id s5mr175834anf.224.1299234634113; Fri, 04 Mar 2011 02:30:34 -0800 (PST) MIME-Version: 1.0 Received: by 10.100.8.2 with HTTP; Fri, 4 Mar 2011 02:30:04 -0800 (PST) In-Reply-To: <20110304100517.GA23249@icarus.home.lan> References: <1299232133.18671.3.camel@pc286.embl.fr> <20110304100517.GA23249@icarus.home.lan> From: Matthias Gamsjager Date: Fri, 4 Mar 2011 11:30:04 +0100 Message-ID: To: Jeremy Chadwick Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-fs@freebsd.org, =?ISO-8859-1?Q?Micka=EBl_Can=E9vet?= Subject: Re: kmem_map too small with ZFS and 8.2-RELEASE X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 04 Mar 2011 10:56:22 -0000 > # Disable ZFS prefetching > # http://southbrain.com/south/2008/04/the-nightmare-comes-slowly-zfs.html > # Increases overall speed of ZFS, but when disk flushing/writes occur, > # system is less responsive (due to extreme disk I/O). > # NOTE: Systems with 8GB of RAM or more have prefetch enabled by > # default. > vfs.zfs.prefetch_disable="1" > > > I wonder if this is still the case since the website you referring to was from 2008 and I guess a lot has changed since then. For example I get horrible performance with prefech disabled. (running on 4 disk striped mirror)