Date: Thu, 11 Mar 2004 12:19:06 +0600 From: Max Khon <fjoe@iclub.nsu.ru> To: "David E. Cross" <crossd@cs.rpi.edu> Cc: Julian Elischer <julian@elischer.org> Subject: Re: JUFS update, and questions. Message-ID: <20040311061906.GA35178@iclub.nsu.ru> In-Reply-To: <1078964168.4345.27.camel@kiki.cs.rpi.edu> References: <Pine.BSF.4.21.0403101546090.15852-100000@InterJet.elischer.org> <1078964168.4345.27.camel@kiki.cs.rpi.edu>
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Hello! On Wed, Mar 10, 2004 at 07:16:09PM -0500, David E. Cross wrote: > > > Journaled UFS Technology Description > > > > > [... much good stuff deleted] > > > > Not requests for features, just requests as to whether you have > > considerred these.. > > > > Does it have the ability to keep the journal on a separate media? > > > > I have sometimes seen the ability to have a separate journal disk used > > to good effect. (not a system filesystem, but a journalled database). > > > > Having a separate journal file/disk elsewhere can speed things up by > > reducing seeks (and other resiliance advantages). > > I have also seen double logging and remote logging... each of which of > > course has advantages and disadvantages.. > > > > Remote logging allows the log to be "replayed" at real time in teh > > remote site, leading to an instantaneously correct remote > > backup/mirror of the local disk. (of course it can not be safely > > accessed except with special safety requirements.. (e.g ability > > to shoot an open vnode if teh inode under it is rewritten) > > > > > > I notice also that you store pre/post stuff and wonder if this can be > > used in conjunction with soft-update's need to sometimes roll-back > > things on the disk? > > It has been thought about, and certainly the design would make it > trivial at a later point to add. The system does all of the work > through vnodes and struct bufs, so they could be backed by "anything" in > the future (well, within reason). But for right now its beyond the > scope of the project. Do you plan to implement data journalling? Regards, /fjoe
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