Date: Thu, 17 Jan 2008 08:15:15 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no> Cc: freebsd-fs@freebsd.org Subject: Re: Can FreeBSD benefit from MacOS X ZFS? Message-ID: <20080117081214.B51764@fledge.watson.org> In-Reply-To: <86sl0xibpz.fsf@ds4.des.no> References: <alpine.BSF.1.00.0801141829370.10868@ibyngvyr.purzvxnyf.bet> <86sl0xibpz.fsf@ds4.des.no>
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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 <morganw@chemikals.org> 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--
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