Date: Wed, 19 Dec 2007 04:39:51 +0100 From: Nikola =?UTF-8?B?TGXEjWnEhw==?= <nikola.lecic@anthesphoria.net> To: "Snow Mountains" <snow.mountains.4@gmail.com> Cc: FreeBSD-questions@FreeBSD.org Subject: Re: Lost FreeBSD slices (labels?) after NetBSD install -- please help!! Message-ID: <20071219043951.58ee4e50@anthesphoria.net> In-Reply-To: <3cf9f8920712181854p1b498d8cve22e5bcdc0ad9fc7@mail.gmail.com> References: <3cf9f8920712132115q341401dbhec96ca1ae3156432@mail.gmail.com> <20071216165127.64661122@anthesphoria.net> <3cf9f8920712181854p1b498d8cve22e5bcdc0ad9fc7@mail.gmail.com>
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On Wed, 19 Dec 2007 03:54:00 +0100 "Snow Mountains" <snow.mountains.4@gmail.com> wrote: =20 [...] > Hello and thanks veeeery much for this response and because you > pointed me to right direction - what to read! It took me some time to > run this and to understand always what I am doing, but it seems to > work! >=20 > testdisk gives me sizes that 100% correspond with _partition_ (:)) > proportions I remember (and some nonsenses about tiny FAT partition > somewhere...). dlfind homepage was incredibly useful for me as newbie > in creating BSD partition labels, and I created bsdlabel file, > carefully calculated offsets, I am happy that former ad1s4a is > mountable so that I can read /etc/fstab! Excellent! Just note that you don't need to calculate offsets; you can use asterisk (*) for all offsets from b: (swap) onward; and you can use * as the size of the last partition, too. > However I have several questions just to be 100% sure. >=20 > a. swap size: by an accident, I have written swapsize (from swapinfo) > of 1024 1kb blocks; it is slightly different from what I get when I > subtract all partition size from total slice's size (as testdisk > reported). What I should trust? Use the value from swapinfo; swap is just that space (unlike sizes that you see in df(1) output: they are not sizes of partitions). The size of slice: you should anyway _first_ run 'bsdlabel-w /dev/ad1s4' -- it will write initial info and the value for c: will be the value you should use. > b. Do I need just bsdlabel -R -e?=20 You probably typoed, either '-R' or '-e' (=3D 'from file' or 'to edit directly'). However, I believe you should use '-B' as well, because bootstrap code was destroyed too, and you won't be able to boot FreeBSD even with recovered partitions. > Is it safe to experiment? Yes, it is. If you write wrong data, it will just not work. Once you get mountable partitions, please fsck(8) them. > c. What to write as fsize, bsize fsize and bsize are 2048 and 16384 if you used all defaults when installed FreeBSD (read newfs(8)).=20 > and bps/cpg? It is completly confusing for me, bps/cpg explanation > from bsdlabel man page is unclear to me, I see that some people use > all zeros and I can not find a clue in various examples... Hmm, yes... Actually, it seems that they can be calculated by comparing data obtained from 'bsdlabel -A /dev/ad1s4...' (look at the top of the output) and from particular 'newfs -N /dev/ad1s4X' (this command doesn't create new file system but just prints all data about how it would be created) -- but after recovery, of course. Read the entire thread that contains this: http://lists.freebsd.org/pipermail/freebsd-questions/2004-January/031603.= html However, I've never been able to find any info in the docs that exactly explains what algorithm newfs(8) uses for this field... Therefore I believe (although I'm not 100% sure) that the only way to get old bps/cpg data is to=20 (1) dump(8) partitions once they work; (2) "bsdlabel -e" bps/cpg of these partitions to zeros; (3) recreate file systems there (this will write new (true) bps/cpg values); (4) restore(8) filesystems. However, if fsck(8) tells you that filesystems are clear once you recover them, I believe you don't have to worry about this. Maybe some filesystem guru can confirm. (According to this reputable source: http://www.onlamp.com/pub/a/bsd/2002/06/27/Big_Scary_Daemons.html last three values are actually ignored...) --=20 Nikola Le=C4=8Di=C4=87 :: =D0=9D=D0=B8=D0=BA=D0=BE=D0=BB=D0=B0 =D0=9B=D0=B5= =D1=87=D0=B8=D1=9B
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