Date: Fri, 16 Jan 2004 12:50:11 -0500 From: Jesse Guardiani <jesse@wingnet.net> To: freebsd-questions@freebsd.org Subject: Level 9 dump size calculation? Message-ID: <bu988k$rm8$1@sea.gmane.org>
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Howdy list, I've got a machine (4.6.1-RELEASE-p10) doing level 9 dumps over SSH to a tape drive on a remote machine over a T1. The machine being backed up looks like this: # df -h Filesystem Size Used Avail Capacity Mounted on /dev/aacd0s1a 300M 52M 225M 19% / /dev/aacd0s1h 2.5G 11M 2.3G 0% /tmp /dev/aacd0s1e 12G 5.3G 5.4G 49% /usr /dev/aacd0s1f 5.8G 1.1G 4.2G 21% /usr/home /dev/aacd0s1g 12G 1.1G 9.6G 10% /var procfs 4.0K 4.0K 0B 100% /proc And my dump command looks like this: ssh "$serverName" -nTc blowfish "/sbin/dump -0us 1000000 -f - /dev/aacd0s1a | gzip -c -3" | gunzip -cd -3 > "$tapeDriveDevice" (machine with tape drive connects to machine to be backed up via SSH, starts the dump on the remote machine [with dump output piping through gzip and then to stdout], decompresses output after it has traveled over the T1 and finally writes it to the tape drive device.) I execute one dump command for /,/usr,/usr/home, and /var. And I get emailed output that looks like this: DUMP: Date of this level 0 dump: Tue Jan 13 06:00:01 2004 DUMP: Date of last level 0 dump: the epoch DUMP: Dumping /dev/aacd0s1a (/) to standard output DUMP: mapping (Pass I) [regular files] DUMP: mapping (Pass II) [directories] DUMP: estimated 54069 tape blocks. DUMP: dumping (Pass III) [directories] DUMP: dumping (Pass IV) [regular files] DUMP: DUMP: 54091 tape blocks DUMP: finished in 130 seconds, throughput 416 KBytes/sec DUMP: level 0 dump on Tue Jan 13 06:00:01 2004 DUMP: DUMP IS DONE Granted, the above commands and output are from a level 0 dump, but my level 9s are performed in exactly the same manner. Here's my question: How do I determine how large the dump output is? The dump man page states that dump uses a blocksize of 10k by default. 54091 tape block * 10k/block = 540910k 540910k/1024 = 528.23M Surely dump isn't expanding my 52M in / to 528.23M!! However: 54091k/1024 = 52.82M (which is very close to how much used space I actually have in /) Is dump incorrectly labeling 54091 as the number of tape blocks when it should instead be labeling 54091 as the number of kilobytes? -- Jesse Guardiani, Systems Administrator WingNET Internet Services, P.O. Box 2605 // Cleveland, TN 37320-2605 423-559-LINK (v) 423-559-5145 (f) http://www.wingnet.net
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