Date: Sun, 5 Oct 2003 12:55:47 -0700 (PDT) From: Don Lewis <truckman@FreeBSD.org> To: randy@psg.com Cc: freebsd-stable@FreeBSD.org Subject: Re: dump faster from remote than from local Message-ID: <200310051955.h95JtlN1049840@gw.catspoiler.org> In-Reply-To: <E1A6EDt-000GST-SF@ran.psg.com>
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On 5 Oct, Randy Bush wrote: > 4.9rc of yesterday > > dump from B->A i.e. from a system on local ether > > DUMP: DUMP: 2082890 tape blocks on 1 volume > DUMP: finished in 478 seconds, throughput 4357 KBytes/sec > ^^^^^^^^^^^^^^^ > and a local dump on A > > DUMP: DUMP: 3560987 tape blocks on 1 volume > DUMP: finished in 3694 seconds, throughput 963 KBytes/sec > ^^^^^^^^^^^^^^ > why is local slower than remote? What are you dumping to on A? If you are dumping to a file on the same spindle, you spend a lot more time doing long seeks. Is there other I/O occuring on the same spindle as the filesystem that you are dumping on A? Could the file system on B have a small number of large files while A has a large number of small files? Has the file system on A been run in a near-full condition for a long period of time so that there are a lot of disk blocks that are poorly placed? What results do you get if you dump each file system to /dev/null on the local machine?
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