From owner-freebsd-hackers@FreeBSD.ORG Wed Jan 12 21:30:45 2005 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9C78116A4CE for ; Wed, 12 Jan 2005 21:30:45 +0000 (GMT) Received: from mx2.netapp.com (mx2.netapp.com [216.240.18.37]) by mx1.FreeBSD.org (Postfix) with ESMTP id D09AE43D1D for ; Wed, 12 Jan 2005 21:30:44 +0000 (GMT) (envelope-from kmacy@netapp.com) Received: from frejya.corp.netapp.com (10.57.157.119) by mx2.netapp.com with ESMTP; 12 Jan 2005 13:30:46 -0800 X-IronPort-AV: i="3.88,118,1102320000"; d="scan'208"; a="120222490:sNHT15646164" Received: from siml3-fe.eng.netapp.com (siml3-fe.eng.netapp.com [10.56.9.153]) j0CLUibr027431; Wed, 12 Jan 2005 13:30:44 -0800 (PST) Date: Wed, 12 Jan 2005 13:30:44 -0800 (PST) From: Kip Macy X-X-Sender: kmacy@siml3.eng.netapp.com To: Siddharth Aggarwal In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: freebsd-hackers@freebsd.org Subject: Re: process checkpoint restore facility now in DragonFly BSD X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 12 Jan 2005 21:30:45 -0000 I've promised Nate to port the functionality to FreeBSD. I'm busy doing some things with the FreeBSD port to Xen at the moment. Checkpointing a process is intrinsically messy for reasons beyond the obvious statefulness of TCP connections. Process state, particularly with regard to devices, is often not cleanly associated with the process in the kernel. What happens if a file that the process had open has gone away? Other issues abound - checkpointing a process pipeline can be made to work, but some work would need to be done on pipes. The list goes on. -Kip On Wed, 12 Jan 2005, Siddharth Aggarwal wrote: > > Hi all, > > I am responding to a post back in Oct 2003 when the checkpointing feature > was announced for DragonFly. I have been doing some research on this, and > have seen some projects that use Xen VMM to achieve checkpoints of guest > OSes. > > So I was looking for inputs from people as to what everyone feels about > checkpointing, whether it should be done at the physical machine level or > VM level. Pros and Cons of each approach, if any further development was > done on DragonFly for checkpoint since then and if it was stopped, why? > Are there serious limitations to checkpointing a physical machine? > > Sorry for such a vague posting, but I thought this would be a good > platform to get some feedback. > > Thanks, > Sid. > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" > -- "Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it." - Brian W. Kernighan