Date: Mon, 12 Jan 2009 12:20:46 +0100 From: Ollivier Robert <roberto@keltia.freenix.fr> To: freebsd-hackers@freebsd.org Subject: Re: 3x read to write ratio on dump/restore Message-ID: <20090112112046.GA52776@keltia.freenix.fr> In-Reply-To: <20090109.095027.-1672857892.imp@bsdimp.com> References: <20090109.095027.-1672857892.imp@bsdimp.com>
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According to M. Warner Losh: > The read kBps was 3x the write kBps. While the dump is going through > the raw device, and the restore is going through the file system, I > can't imagine why we'd have such a huge difference that would be utter > consistent for the whole 15 hour run. dump launches several processes to read the raw device and use a buffer between them whereas restore is single process. When copying from disk to disk, I often use team (sysutils/team) to stream. -- Ollivier ROBERT -=- FreeBSD: The Power to Serve! -=- roberto@keltia.freenix.fr Dons / donation Ondine : http://ondine.keltia.net/
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