Date: Wed, 30 Sep 2009 11:26:55 -0400 From: Jerry McAllister <jerrymc@msu.edu> To: PJ <af.gourmet@videotron.ca> Cc: Polytropon <freebsd@edvax.de>, freebsd-questions@freebsd.org Subject: Re: backups & cloning Message-ID: <20090930152655.GB27266@gizmo.acns.msu.edu> In-Reply-To: <4AC2C6FE.5030507@videotron.ca> References: <4AC29BE6.4000505@videotron.ca> <alpine.BSF.2.00.0909291759110.44648@wonkity.com> <4AC2B3BB.4080807@videotron.ca> <20090930040733.91cc32d4.freebsd@edvax.de> <4AC2C6FE.5030507@videotron.ca>
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On Tue, Sep 29, 2009 at 10:48:30PM -0400, PJ wrote: > Polytropon wrote: > > On Tue, 29 Sep 2009 21:26:19 -0400, PJ <af.gourmet@videotron.ca> wrote: > > > >> But what does that mean? But ad2s1a has just been newfs'd - so how can > >> it be dumped if its been formatted? > >> > > When you're working on this low level, triple-check all your > > commands. Failure to do so can cause data loss. In the example > > you presented, ad1 was the source disk, ad2 the target disk. > > You DON'T want to newfs your source disk. > > > >> And what exactly does stdout mean? > >> > > > > This refers to the standard output. In most cases, this is the > > terminal, the screen, such as > > > > # cat /etc/fstab > > > > will write the /etc/fstab to stdout. If you redirect it, for > > example by using > or |, you can make stdout a file, or the > > input - stdin - for another program. > > > > This is how the dump | restore process works: It leaves out > > the "use the tape" or "use the file", but instead directs the > > output of dump - the dump itself - to the restore program as > > input to be restored. > > > >> What is dump doing? outputting what to where exactly? > >> > > The dump program is outputting a dump of the specified partition > > to the standard output, which in this case is directly trans- > > mitted to the restore program, which "picks it up" and processes > > it = restores it. > > > >> I don't see it or > >> should I say, understand this at all. > > > > Have a look at the command line again, simplified: > > > > # dump -0 -f - /dev/ad0s1a | restore -r -f - > > > > Run the dump program, do a full backup of the 1st partition of > > the 1st slice of the 1st disk, write this dump to the standard > > output, pipe this output to the restore program, do a full > > restore, read the dump to be restored from standard input. > > > >> and then the restore is from what > >> to where? > > > > The restore program gets the dump to be restored from the standard > > input - remember, that's the output of the dump program - and > > writes it to the current working directory. That's the reason > > why you should always check with > > > > # pwd > > > > in which directory you're currently located, because that will > > be the place where the restored data will appear. > > > >> "write error 10 blocks into volume 1 > >> do you want to restart:" > >> > > > > Could you present the command you're actually using, especially > > with where you issued it from? > > > Duh.... I think I see where this is leading... I'm pretty sure it was > issued from / which makes it redundant, right? I should have issued it > from somewhere else, like from home, usr or whatever but not from / as > that is what I was trying to dump.... :-[ No, that is not a problem. You can be in any directory and do the dump command, except if you want that restore to work you have to be in the receiving filesystem/directory. I just noticed that I missed that you were newfs-ing the wrong partition. That was the one you wanted to read from and your newfs would wipe out everything on it. If you do the newfs - a good idea - it has to be on the new filesystem you will be writing to. ////jerry > > > >> The first time I tried with -L the error was 20 blocks... > >> Both the slices for dump from and to are same size (2gb) and certainly > >> not full by a long shot ( if I reccall correctly, only about 14% is used) > >> > > > > I'm not sure where you put the dump file. "Write error" seems > > to indicate one of the following problems: > > a) The snapshot cannot be created. > > b) The dump file cannot be created. > > > > > > > > > >> And what's this about a snapshot? AFAIK, I'm not making a snapshot; > >> anyway, there is no long pause except for the dumb look on my face upon > >> seeing these messages. > >> > > > > Check "man dump" and search for the -L option. The dump program, > > in order to obtain a dump from a file system that's currently in > > use, will need to make a snapshot because it cannot handle data > > that is changing. So it will dump the data with the state of the > > snapshot, allowing the file system to be altered afterwards. > > > > > > > > > >> As it is, I am currently erasing the brand new 500gb disk on which I > >> want to restore. > >> > > > > Excellent. > > > > > > > > > >> Things started out really bad... don't u;nderstand what is going on. > >> > > > > Polite question: Have you read the manpages and the section in the > > Handbook? > > > Yes... but my brain can't handle it all so quickly... and being as > impatient as I am, I tend to miss things on the run... it usually comes > to me sooner or later... unfortunately, it's more often later than > sooner... I've been reading the stuff in the man pages, and getting more > confused by googling... Actually, I've been trying to get things > straightened ot for at least 3 days already. > > > > > > > >> I > >> installed a minimal 7.2, booted up and turned to another computer to do > >> some serious work. About 2 hours and 49 minutes later I notice messages > >> on the 7.2 about a page fault or something like that and then the system > >> reboots. > >> > > > > This often indicates a hardware problem... > > > Well, that's why I'm really checking my new disk... but it could be the > motherboard... I've always suspected it had something of a glitch in it > ever since I got it... I don't think just a slower cpu should give it so > many problems... a twin computer has the same hardware except for the > cpu and it gives far less problems - only MS related. > > > > > > > >> Obviously with errors... but then I reboot again and it comes > >> up... I tried som copying from another disk and ended up with the disk > >> all screwed up... > >> > > > > How that? > > > > > > > > > >> yet the Seagate Seatools for Dos doesnt find any > >> errors on it; > >> > > > > There's smartmontools (program: smartctl) for FreeBSD in the ports. > > It can check various errors of modern hard disks. > > > > > > > > > >> Partition magic found an error but couldn't fix it, so now > >> Im wiping the whole thing and will try to reinstall tomorrow. Doesn't > >> make sense. > >> > > > > What error was this? > > > Something about a boot sector - this is not the first time I have seen > this identical error but on much older hdd's, though still satas. > This does make me think that these problems are of hardware origin - > motherboard or sata connectors - I find they are rather Disneyesque > (Mickey Mouse) or just plain flimsy. > > Time to hit the sack... another day of computer frustration coming up... > I'm under pressure to lear Flash and have to set up a reliable server to > test a site I am designing and setting up. Have to do it myself... can't > afford about anything today. :-( > Thanks again for the input. > > > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to "freebsd-questions-unsubscribe@freebsd.org"
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