Date: Sat, 7 Apr 2007 10:35:56 +0100 (BST) From: Mike Wolman <mike@nux.co.uk> To: "R. B. Riddick" <arne_woerner@yahoo.com> Cc: freebsd-fs@FreeBSD.org, freebsd-questions@freebsd.org Subject: Re: some thoughts about gmirror Message-ID: <20070407103057.P20396@nux.eros.office> In-Reply-To: <219395.34786.qm@web30302.mail.mud.yahoo.com> References: <219395.34786.qm@web30302.mail.mud.yahoo.com>
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Rsync is a great tool however if you try to rsync a filesystem with hundreds of thousand files in it the file list can use quite a large amount of bandwidth even if only a single file has changed - if you were keeping track of the blocks which had changed then you do not need to generate this list and simply send over the changed blocks. I was not thinking the remote side would mount the image unless the primary site was offline/unavailable. Mike. On Fri, 6 Apr 2007, R. B. Riddick wrote: > --- Mike Wolman <mike@nux.co.uk> wrote: >> It could also be used for asynchronous mirrors over slow links, if the log >> device was always written to first then the write latency for long distant >> links could be removed. Im not sure if it would be possible to achieve >> this using just a modified ggatec instead which has a local device used >> as a write cache. >> > Sounds like rsync can already do that (I am not sure right now, if rsync can > find updated areas within a large file, or if it just copies the while updated > file even if it is a large one)... > > Furthermore the remote consumer of that gmirror couldnt be mounted RW, if it > uses UFS, because UFS doesnt allow multiple RW mounts at the same time... > > -Arne > > > > ____________________________________________________________________________________ > Food fight? Enjoy some healthy debate > in the Yahoo! Answers Food & Drink Q&A. > http://answers.yahoo.com/dir/?link=list&sid=396545367 > >
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