From owner-freebsd-fs@FreeBSD.ORG Thu Jan 17 08:15:16 2008 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 0210616A468 for ; Thu, 17 Jan 2008 08:15:16 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.freebsd.org (Postfix) with ESMTP id CC3B513C46E for ; Thu, 17 Jan 2008 08:15:15 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id 6DCB0472DF; Thu, 17 Jan 2008 03:15:15 -0500 (EST) Date: Thu, 17 Jan 2008 08:15:15 +0000 (GMT) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= In-Reply-To: <86sl0xibpz.fsf@ds4.des.no> Message-ID: <20080117081214.B51764@fledge.watson.org> References: <86sl0xibpz.fsf@ds4.des.no> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="621616949-630750762-1200557715=:51764" Cc: freebsd-fs@freebsd.org Subject: Re: Can FreeBSD benefit from MacOS X ZFS? 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: Thu, 17 Jan 2008 08:15:16 -0000 This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --621616949-630750762-1200557715=:51764 Content-Type: TEXT/PLAIN; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE On Thu, 17 Jan 2008, Dag-Erling Sm=F8rgrav wrote: > Wes Morgan writes: > >> As the subject says... Can FreeBSD benefit from the macos port of zfs? I= =20 >> know this is a VERY new announcement, but not knowing much about macos x= in=20 >> general I'm wondering how much it might help our tree, with respect to b= oth=20 >> the memory and 32-bit issues. Just throwing it out there for discussion,= if=20 >> anyone has any knowledge of both. > > Did you miss the part where Apple no longer sell 32-bit computers? Actually, the first generation MacBook/MacBook Pro's donly have 64-bit=20 support, and both the kernel and user address spaces are 32-bit on those=20 systems. They did, however, have PAE to support larger physical memories.= =20 More recent Intel Macs have 64-bit address support for userspace but 32-bit= =20 kernels. Unlike with FreeBSD, the Mac OS X kernel runs in its own dedicate= d=20 32-bit address space rather than splitting a single 32-bit address space wi= th=20 userspace. This leads to greater system call overhead (system calls requir= e a=20 full context switch) but much more kernel address space. My impression has= =20 been that Apple has also had challenges dealing with ZFS's run-away resourc= e=20 use, however... Robert N M Watson Computer Laboratory University of Cambridge --621616949-630750762-1200557715=:51764--