Date: Mon, 3 Feb 2014 08:44:05 +0100 From: Matthias Apitz <guru@unixarea.de> To: freebsd-questions@freebsd.org Subject: dump(8) && -b option Message-ID: <20140203074405.GA10184@sh4-5.1blu.de>
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Hello, Last weekend I was playing around with the dump options to improve the dump speed to my external USB drive. I tried using the -b option to increase the blocksize of the written junks: # dump -0auL -b 100 -f - /usr ... DUMP: finished in 40 seconds, throughput 7485 KBytes/sec # dump -0auL -b 10 -f - /usr ... DUMP: finished in 70 seconds, throughput 4274 KBytes/sec with -b 1000 the dump hangs forever: # dump -0auL -b 1000 -f - /usr ... DUMP: dumping (Pass III) [directories] (hangs) on of its child is doing this where fd 3 is the device to be backed up: pread(0x3,0x28809000,0x1000,0x89909000,0xa5,0xbfbfcc88) ERR#5 'Input/output error' pread(0x3,0x28809000,0x1000,0x89909000,0xa5,0xbfbfcc88) ERR#5 'Input/output error' pread(0x3,0x28809000,0x1000,0x89909000,0xa5,0xbfbfcc88) ERR#5 'Input/output error' pread(0x3,0x28809000,0x1000,0x89909000,0xa5,0xbfbfcc88) ERR#5 'Input/output error' pread(0x3,0x28809000,0x1000,0x89909000,0xa5,0xbfbfcc88) ERR#5 'Input/output error' Why is this? Maybe the best is doing the write to the disk with dd(1), for example with # dump -0auL -f - /usr | dd bs=8m > /dev/da0s1a/usr.dmp Any comments? Thanks matthias -- Matthias Apitz | /"\ ASCII Ribbon Campaign: www.asciiribbon.org E-mail: guru@unixarea.de | \ / - No HTML/RTF in E-mail WWW: http://www.unixarea.de/ | X - No proprietary attachments phone: +49-170-4527211 | / \ - Respect for open standards
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