Date: Sun, 10 Jun 2012 20:15:52 -0400 From: Robert Huff <roberthuff@rcn.com> To: "Ronald F. Guilmette" <rfg@tristatelogic.com> Cc: freebsd-questions@freebsd.org Subject: Re: Making a bootable backup (hard)disk... how? Message-ID: <20437.14520.364554.528919@jerusalem.litteratus.org> In-Reply-To: <48774.1339367039@tristatelogic.com> References: <alpine.BSF.2.00.1206100543280.75580@wonkity.com> <48774.1339367039@tristatelogic.com>
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Ronald F. Guilmette writes: > Warren? Just a couple more quick questions. You recommend: > > >> dump -C16 -b64 -0uanL -h0 -f - /usr | (cd /mnt && restore -ruf -) > > I'm real curious about you suggestions for the -C and -b values. > > I have what amounts to a personal workstation. Yea, OK, it is running > mail, web, and FTP servers also, but fundementailly, it is not that busy > most of the time. And it's got 4GB of main installed. On average, I > suspect that I ain't even using half of that. > > Given all that, why shouldn't I specify (e.g.): -C512 -b1024 ? > > Wouldn't that all make the dump go faster? There are many possible obstacles to faster dump speed; enumerating them is left as an exercise for the reader. As it happens, I have a set-up very similar to what you describe ... except with 8g of memory. A few years ago I did some testing with various cache sizes (as part of diagnosing other problems) and ended up with C=32. (I should probably run the tests again, given some hardware changes since.) That machine's level 0 runs tonight; I will try to remember to (retain and) post the results. Robert Huff
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