On 27/10/2007 Andreas Jung wrote: >>> If you create a local copy, it is safe. If you rsync a running Data.fs, >>> it is not safe. In this case you create a local copy and rsync the copy. >> >> but if rsync is unsafe only because it takes long time, and changes on the >> instance during the copy process could cause a corrupted Data.fs to be >> backuped, then theoretically this could happen for a local copy as >> well, right? > > Think twice about your last sentence. What should cause a local *copy* > to be changed??
zope might write to the Data.fs while it is copied, thus an inconsistent copy would be backuped, even inside one filesystem. i've asked in #debian on freenode as i wasn't sure, here's the log: < mejo> if i copy a large file inside a mounted filesystem (ext3), is it possible that the file is changed during the copy process? < Wyzard> mejo: Yes, it's possible that something else can write to the file while you're copying it < mejo> because i asked on the zope-users mailinglist if i could backup the global Data.fs (database) while the daemon is running, and someone answered: < mejo> If you create a local copy, it is safe. If you rsync a running Data.fs it is not safe. In this case you create a local copy and rsync the copy. < Wyzard> mejo: Making a local copy is faster, so it'd be safer, but still not completely safe < mejo> exactly, that's what i thought as well. < mejo> but when i wrote that, he replied: < mejo> Think twice about your last sentence. What should cause a local *copy* to be changed?? < mejo> so he's wrong? < Wyzard> I'd say he's wrong < Wyzard> A local copy isn't instantaneous, and Zope changes the file while it's being read < wols_> he is wrong yes < mejo> thanks. is it ok for you if i quote you in my reply mail? < Wyzard> mejo: sure < wols_> mejo: while copying zope could change the database and create an inconsistent state greetings, jonas
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