Hi, Is it possible to clarify what resides behind the concept of levels regarding dump(8) ? For me the level 0 is understood to be a complete dump of all files on at a given mount point and all subdirectories. But I can't figure out what upper levels are. Regards
A level 0 dumps includes all files. A level n dump are all the files that have changed or were added since the last level n - 1 dump. -Otto
My dump level 1 dumps all the files again. How to let it dump based on the lower level ? I did as follows : sudo dump -0ua -f /mnt/tera/backup/2010.02.18_www.0 /var/www/htdocs/ sudo dump -0ua -f /mnt/tera/backup/2010.02.18_www.1 /var/www/htdocs/ Regards
On Thu, Feb 18, 2010 at 11:21 PM, Jean-Francois <firstname.lastname@example.org> wrote: You did two level 0 dumps, so what else you expect ?;)
Mistyped the mail. I proceed in this way and get two times the same dump. Is it normal ? sudo dump -0ua -f /mnt/tera/backup/2010.02.18_www.0 /var/www/htdocs/ sudo dump -1ua -f /mnt/tera/backup/2010.02.18_www.1 /var/www/htdocs/
Show your dump output. Of both runs. -Otto
Not sure to understand the subtle of the man page explanations regarding the dump of different nature of mount points. Just one additional information, the dump of higher levels work when I dump /var but not /var/htdocs. $ sudo dump -0ua -f /mnt/tera/backup/2010.02.18_www.0 /var/www/htdocs/ DUMP: Ignoring u flag for subdir dump DUMP: Dumping sub files/directories from /var DUMP: Dumping file/directory /var/www/htdocs/ DUMP: Date of this level 0 dump: Fri Feb 19 21:47:18 2010 DUMP: Date of last level 0 dump: the epoch DUMP: Dumping /dev/rwd0g (/var) to /mnt/tera/backup/2010.02.18_www.0 DUMP: mapping (Pass I) [regular files] DUMP: mapping (Pass II) [directories] DUMP: estimated 188530 tape blocks. DUMP: Volume 1 started at: Fri Feb 19 21:47:21 2010 DUMP: dumping (Pass III) [directories] DUMP: dumping (Pass IV) [regular files] DUMP: 196284 tape blocks on 1 volume DUMP: Date of this level 0 dump: Fri Feb 19 21:47:18 2010 DUMP: Volume 1 completed at: Fri Feb 19 21:47:33 2010 DUMP: Volume 1 took 0:00:12 DUMP: Volume 1 transfer rate: 16357 KB/s DUMP: Date this dump completed: Fri Feb 19 21:47:33 2010 DUMP: Average transfer rate: 16357 KB/s DUMP: Closing /mnt/tera/backup/2010.02.18_www.0 DUMP: DUMP IS DONE $ sudo dump -1ua -f /mnt/tera/backup/2010.02.18_www.1 /var/www/htdocs/ DUMP: Ignoring u flag for subdir dump DUMP: Subdir dump is done at level 0 DUMP: Dumping sub files/directories from /var DUMP: Dumping file/directory /var/www/htdocs/ DUMP: Date of this level 0 dump: Fri Feb 19 21:47:36 2010 DUMP: Date of last level 0 dump: the epoch DUMP: Dumping /dev/rwd0g (/var) to /mnt/tera/backup/2010.02.18_www.1 DUMP: mapping (Pass I) [regular files] DUMP: mapping (Pass II) [directories] DUMP: estimated 188530 tape blocks. DUMP: Volume 1 started at: Fri Feb 19 21:47:39 2010 DUMP: dumping (Pass III) [directories] DUMP: dumping (Pass IV) [regular files] DUMP: 196284 tape blocks on 1 volume DUMP: Date of ...
There you go. Incremental dumps should be done at the filessytem level.
On Fri, Feb 19, 2010 at 12:49 PM, Jean-Francois <email@example.com> wrote: The key is the last sentence of this paragraph from the dump(8) manpage: files-to-dump is either a mountpoint of a filesystem or a list of files and directories on a single filesystem to be backed up as a subset of the filesystem. In the former case, either the path to a mounted filesystem or the device of an unmounted filesystem can be used. In the latter case, certain restrictions are placed on the backup: -u is ignored, the only dump level that is supported is -0, and all of the files must reside on the same filesystem. So, if you're not dumping an entire filesystem, then you always get a full (level 0) dump. (Why? At least part of the reason is that if you're not doing the full filesystem, inode ctime isn't sufficient to determine whether a file would be new to the dump.) Philip Guenther
Is it possible to clarify further this particular para of dump(8), I cant understand the differences that are explained here between the nature of the mount points and file systems and the relationship to what is prohibited (L+1 dumps are). Thanks. Regards
You are doing two level 0 dumps. The seconds invication should use -1ua Also, note that these dumps are filesystem dumps. A whole filesystem is dumped this way.
Are all dump levels packed into the same one file like I seem to understand ? As far as I am concerned I dump in this way : dump -0u -f /mnt/backup/backup /mnt/donnees/ dump -1u -f /mnt/backup/backup /mnt/donnees/ ... This is correct, is'nt it ? Regards.
That's incorrect. In your first command you do a full backup of /mnt/donnees and save it to the file /mnt/backup/backup. With your second command you do an incremental backup which saves only the changed files between the first backup and now. You save it on the same file which means that you overwrite/delete the first backup. If you wanted to restore something you would be able to restore only the changed files between first and second backup. You need to have both files (stored separately) to do full -current (tm) restore of your files. If you wander why to use different dump levels the answer is for organizing the backup policy and saving a hell lot of space/tapes than doing always full backups. regards, Giannis
from dump(8)'s man page: -0-9 Dump levels. A level 0, full backup, guarantees the entire file system is copied (but see also the -h option below). A level number above 0, incremental backup, tells dump to copy all files new or modified since the last dump of a lower level. The de- fault level is 0. So a dump of level 0 is a complete dump, a dump of level 1 is a dump of all files since last dump 0, a dump of level 2 is a dump of all files since last dump of level 1, and so on Gilles -- Gilles Chehade freelance developer/sysadmin/consultant http://www.poolp.org
Dump levels other than 0 allow you to make partial dumps. I used to do dump level 0's at the start of the month. Then from Monday to Thursday I'd to dump 9's. Each dump would save things from the previous 9 (or 0 the first time). Friday's I'd do a level 8. Thus each M-T I'd save the days work, Friday I'd save the weeks work. Then at the start of the next month a level 0 dump would make a copy of everything. Each dump level going downwards saves all the data from previous (higher) numbered dumps. --STeve Andre'
Just to confirm or unconfuse myself if you're doing dump 9s on Monday to Thursday aren't you getting everything from the previous days each dump rather than just the day before? I thought to get just the files changed on a particular day you'd have to go: Mon - dump 5 Tues - dump 6 Wed - dump 7 Thurs - dump 8 Fri - dump 4 -- Dethink to survive - Mclusky
A dump at level N includes everything modified since the last dump at N-1 or lower. Thus, for example, if on Monday we do a level 0 dump of /foo, and then on Tuesday, we do a level 1 dump of /foo, that second dump will contain everything that's changed in the last day. If on Wednesday, we do a level 3 dump of /foo (note that I skipped level 2 on purpose) then we will have everything that changed since Tuesday, since 3 > 1. If on Thursday, we NOW do a level 2 dump of /foo, we will have everything that changed since the level 1 on Tuesday -- two days' worth of changes. This all works as planned provided you give "u" flag to dump, which instructs it keep track (in /etc/dumpdates) of which filesystems it has dumped and when. Note (a) that filesystems are tracked by device, so that if you umount /foo and remount it as /bar, the right thing happens and (b) the timestamp used is the time that the dump BEGINS, but it is not written into the file until the dump ENDS. (This is part of the set of mechanisms which deal with changes that take place while dump is running.) Dump's various levels provide a lot of ways to minimize one or more of (1) dump run time (2) dump output size (3) number of dumps required to restore a failed filesystem. For example, if you did level 0 dumps every day, you would maximize (1) and (2) but minimize (3), since it would always be 1. For another example, if you did level 0 dumps on Sunday and 1-6 Monday-Saturday, then you would cut down (1) and (2) considerably six days a week, but you might need to restore as many as 7 dumps which means you've pushed (3) fairly high. So choosing which scheme is appropriate for you requires having knowledge of your environment and answering questions like: - how much backup space do you have? - do you lose entire disks often? - do your users screw up and require restores often? - do you have an open or limited backup window? - what are you backing up? - does the data you're backup up compress ...
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