Memory requirement for fsck_ffs in recovery session

Polytropon freebsd at
Tue Aug 19 16:27:35 UTC 2008


I have another problem trying to recover my data that has been "destroyed"
(in fact, it's just inaccessible because the inode at the entry od my
home directory died).

I'm using a dd image which reproduces the exact error of the defective
hard disk partition, I run fsck_ffs on a md type vnode.

	# mount -t ufs /dev/ad2s1h /mnt
	# mdconfig -a -t vnode -u 0 -f /mnt/home/poly/rescue/ad0s1f.dd
	# fsck_ffs /dev/md0

Up to this point, I tried to use fsck_ffs from FreeBSD version 7, which
always left me with this:

	fsck_ffs: bad inode number 306176 to nextinode

Examining fsck_ffs, I found ot that lastvalidinum = 306175, but that's
a story for another time. :-) I always thought I needed to modify the
file system so fsck_ffs could do its job, now I think I rather would
modify fsck_ffs so it would skip these errors I can't see any reason

Out of curiosity, I booted my system with a done version 5 installation
harddisk I had extracted from a system some years ago, and guess what?
fsck_ffs version 5 seemed to do more than version 7 did! This is what I

	fsck_ffs: cannot alloc 1073796864 bytes for inoinfo

My question: My machine has 768 MB RAM (512 + 256 MB SDR-SDRAM) and
fsck_ffs seems to request 1 GB RAM (1073796864/1024/1024/1024). Is
it possible to provide this amount of RAM via a harddisk backed RAM
disk or a swap partition?

I think I'll try ffsck_ffs version 6 from a PC-BSD installation that
must be somewhere around here...

Thanks for help!

>From Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...

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