Re: Need Help restoring a filesystem on an external drive WD 'My Book'
- Date: Tue, 28 Nov 2017 19:48:51 +0100
- From: "Thomas Schmitt" <scdbackup@xxxxxxx>
- Subject: Re: Need Help restoring a filesystem on an external drive WD 'My Book'
> and I doubt if I understand what is a 'sparse' superblock
It's not a bad sign, as it seems:
"The first version of ext2 (revision 0) stores a copy at the start of
every block group, along with backups of the group descriptor block(s).
Because this can consume a considerable amount of space for large
filesystems, later revisions can optionally reduce the number of backup
copies by only putting backups in specific groups (this is the sparse
> Command line: TestDisk /log /dev/sdb
> 1 P partition_map 1 63 63
Looks like it recognized a GUID partition table (GPT).
> 3 P HFS 262208 1953525151 1953262944
This would be the ext filesystem's partition.
The following superuser command establishes a read-only loop device which
begins at the given block:
losetup -o $(expr 262208 '*' 512) -r -f /dev/sdb
(Contrary to the man page, losetup -f does not tell me the used device path.
I have to run
losetup -l | fgrep /dev/sdb
to learn that it's /dev/loop0.)
> Linux 262208 1953525151 1953262944
> ext2 blocksize=4096 Large file Sparse superblock, 1000 GB / 931 GiB
> recover_EXT2: "e2fsck -b 32768 -B 4096 device" may be needed
This is probably the normal superblock in that partition.
But running e2fsck might cause the end of the remaining data in the
I'd try to mount the loop device and hope to recover some files.
When this is queezed out, then maybe a run of e2fsck might recover more
valid files ... or ruin the filesystem.
Have a nice day :)