Date: Mon, 3 Feb 2014 22:26:05 +0100 From: Roland Smith <rsmith@xs4all.nl> To: Matthias Apitz <guru@unixarea.de> Cc: freebsd-questions@freebsd.org Subject: Re: dump(8) && -b option Message-ID: <20140203212605.GA49118@slackbox.erewhon.net> In-Reply-To: <20140203074405.GA10184@sh4-5.1blu.de> References: <20140203074405.GA10184@sh4-5.1blu.de>
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[-- Attachment #1 --] On Mon, Feb 03, 2014 at 08:44:05AM +0100, Matthias Apitz wrote: > > 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? Input/output error indicates that a file could not be read. Did you run a fsck before dump? Are you trying to dump a live filesystem? On 9.0 doing dumps of a live filesystem that has journaled soft-updates (SU+J) enabled were broken. I am not sure if this has been fixed already. > 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 For now, the best thing AFAIK is not to use -L but to dump the filesystem from single user mode when it is not mounted. Roland -- R.F.Smith http://rsmith.home.xs4all.nl/ [plain text _non-HTML_ PGP/GnuPG encrypted/signed email much appreciated] pgp: 1A2B 477F 9970 BA3C 2914 B7CE 1277 EFB0 C321 A725 (KeyID: C321A725) [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (FreeBSD) iEYEARECAAYFAlLwCW0ACgkQEnfvsMMhpyXNmwCgkbH5GUuEIosSdQTj9zGbBKLV WmEAn0GVrEb/eqZelrS337/gb5zGIt1z =JO0V -----END PGP SIGNATURE-----
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