detached a mounted ufs filesystem

Xihong Yin xyin at
Sun Jun 13 02:45:18 UTC 2010

'fdisk /dev/da0' output is

******* Working on device /dev/da0 *******
parameters extracted from in-core disklabel are:
cylinders=14593 heads=255 sectors/track=63 (16065 blks/cyl)

Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=14593 heads=255 sectors/track=63 (16065 blks/cyl)

Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
 start 63, size 234436482 (114470 Meg), flag 80 (active)
 beg: cyl 0/ head 1/ sector 1;
 end: cyl 1023/ head 254/ sector 63
The data for partition 2 is:
The data for partition 3 is:
The data for partition 4 is:

I tried 'fsck_ufs /dev/da0', it says

** /dev/da0
Cannot find file system superblock
ioctl (GCINFO): Inappropriate ioctl for device
fsck_ufs: /dev/da0: can't read disk label

I forget what layout the disk has. Normally I used /dev/da0s1d to mount the disk.

What the next step should I do?


----- Original Message -----
From: Polytropon
Sent: 06/12/10 08:16 PM
To: Xihong Yin
Subject: Re: detached a mounted ufs filesystem

On Sat, 12 Jun 2010 19:46:26 -0400, "Xihong Yin" <xyin at> wrote: > I accidentally detached my usb external hard drive without > umount it. The hard driver filesysystem is ufs. Now I can't > mount it because I can't see the slices. What I get is only > da0 and da0a in the /dev directory. Is there a way to fix > the filesystem? First of all, what does # fdisk da0 say? Has there already been a try to run fsck for this disk? Which layout (slices, partitions) should the disk contain? In case you lost "just" a partition table, install the program "testdisk" from ports or packages. If you don't have a backup of the data on the disk, keep in mind that everything you do is basically able to do more damage. If you have enough hard disk space, make a dd copy of the whole disk first and continue working with this 1:1 copy. Before you start using forensic tools, you should try to get the disk back into action. If this fails, we'll talk about how to recover files. :-) -- Polytropon M
 agdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... _______________________________________________ freebsd-questions at mailing list To unsubscribe, send any mail to "freebsd-questions-unsubscribe at"

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