by notto » Sun Oct 28, 2012 6:06 am
backuping huge profiles creates nonstandard zip file (>4gig zip)
having a huge problem with tebe.
just recently, i moved from windowsxp-32bit firefox with febe just nicely over to win7-64bit
the fbu file of febe was 260megabytes, all went fine
then i tried to tackle thunderbird on the same winxp 32bit machine, and the resulting tbu file was still 6+gigabytes in size, the original profile was over 9gigabytes on the local disk
i transferred the tbu file over to the win7 64bit machine and installed tebe into default first profile of thunderbird, and tried to make it restore the tbu file/profile from it to a newly created additional thunderbird profile. it never did anything besides animating the restore window bar.
first I had thought that the new tb profile needed to be executed/started at least one time, as the profiledirectory was simply empty, and no default thunderbird profile files and subdirectories were present.
then i decided to delete this profile and create one separately newly with thunderbird.exe -prolfilemanager
and start into it at least one time
thunderbird created about 15megabyte of files and subfolders as default into it.
then i went back to first default profile with tebe and selected the tbu file again and told it to restore to that second profile
i checked in the dosbox/cmd and saw, that the default 15megabytes were gone as soon as the animation restore window was running, so thunderbird/tebe did do something in that profile directory. so far so good.
then i used processexplorer and processmonitor (and similar tools, e.g.by sysinternals/microsoft) to check what thunderbird app was doing with files and so on.
i figured that it indeed loaded and checked the 6+gigabyte tbu file but closed it simply right away after it and then never did anything meaningful again only thunderbird.exe was working some true type fonts or so from windows fonts directory. i left it running an hour or two but it never went anyway (restore animation window)
oh, and yes, I know about all this dom script timeout values and all in about:config, that is not the issue here
so eventually i tried to check with 7zip (or any zipper at all) the created tbu file (as its supposed to be in zip standard)
7zip could open the file and list filenames and directory contents, also compression algorithm and whole archive size and compression ration and all. but when 7zip tried to test the tbu archive or extract anything or whatever, it complained for all and every file, that compression algorithm wasnt supported.
then i tried 7zip to check the firefox backup file .fbu, that was only 260megabytes. 7zip could view the file and its contents and also check the archive and extract stuff fromit. as i said before the firefox migration backup/restore scenario from winxp32bit to win7x64 went just fine as I am using my migrated firefox instance to write here into the forum.
so I compared the 7zip displayed information of the fbu and tbu file, and both look very similar, as they only use the deflate achiving standard that has been defined ages ago for the zip standard and unix encoding style or so, I am not that expert in this stuff.
then it came to my mind the infamous hugefile trouble in all kind of operating systems and libraries in the past decades. I think I remember that the original zip fileformat was never intended for files larger than 4gigabyte or even only 2gigabytes. only at a later time zip (pkzip? or winzip folks or some group or standardising associations and folks) were extending zip fileformat to go beyond 32bit filesizes and more, aes encryption, zip splitting into multiple volumes and so on.
so to make this story short, I have really a huge thunderbird profile as raw files on disk already 9+gigabytes, and the tebe tries to pack/zip it into the tbu file and still leaves it at 6+gigabytes.
apparently the packing into zip fileformat uses the ancient classic original old zipfileformat and messes up the archive and creates nonstandard nondefault incompatible zipfile that is beyond the standards and specifications
no zipper can read this file properly, as there is also probably bufferoverflows or tags and flags out of boundary and out of allowed values and impossible variable values and all that.
so how are we gonna backup/restore handling huge firefox/thunderbird profiles that go beyond the limits of zip filesizes?
can anyone solve this trouble really quickly by going for newer zipfile formats, or even using better format such as 7zip native format or rar? probably 7zip format would be best, but I dont know if these extensions such as tebe/febe would then need object code and dll or libaries to be able to use 7zip algorithm or how the stuff with zipping is currently realized? is tebe/febe using mozilla api to call a zipping function and routine, or does the extension supply some machine/object code to do its own zipping?
any help possible here, or do I have to try mozbackup, although I wonder if mozbackup is still compatible with my thunderbird 16.0.x (also firefox 16.0.x) at all, as I see hardly any updates of mozbackup any more on their pages, forums or blog. also if mozbackup would be able to handle this huge datasize as it also creates its own packed file, and I think they also use zip, as I can remember of looking into mozbackup backup files with 7zip, wondering if they use default old zip fileformat as well or if they can handle newer zip mechanisms of larger than 32bit files?
other than that I suppose I need to copy/move my files from winxp thunderbird manually to win7x64bit and mess with prefs.js and all that crap, path strings in those config files and more.
is there maybe a workaround possible, in generating MULTIPLE zip files (tbu/fbu) when those files reach the 2gigabyte or 4gigabyte limits when backuping/restoring profiles?
any helpful insight here? thanks for listening and reading. many regards.