o2image - Copy or restore OCFS2 file system meta-data
o2image [-r] [-I] device image-file
o2image copies the OCFS2 file system meta-data from the device to the
specified image-file. This image file contains the file system
skeleton that includes the inodes, directory names and file names. It
does not include any file data.
This image file can be useful to debug certain problems that are not
reproducible otherwise. Like on-disk corruptions. It could also be
used to analyse the file system layout in an aging file system with an
eye towards improving performance.
As the image-file contains a copy of all the meta-data blocks, it can
be a large file. By default, it is created in a packed format, in
which all meta-data blocks are written back-to-back. With the -r
option, the user could choose to have the file in the raw (or sparse)
format, in which the blocks are written to the same offset as they are
on the device.
debugfs.ocfs2 understands both formats.
o2image also has the option, -I, to restore the meta-data from the
image file onto the device. This option will rarely be useful to end-
users and has been written specifically for developers and testers.
-r Copies the meta-data to the image-file in the raw format. Use
this option only if the destination file system supports sparse
files. If unsure, do not use this option and let the tool create
the image-file in the packed format.
-I Restores meta-data from the image-file onto the device. CAUTION:
This option could corrupt the file system.
-i Interactive mode - before writing out the image file print it's
size and ask whether to proceed. This setting only applies when
'-I' is not specified. It can be useful when the file system
holding the image is low on disk space and the user might need
to free up space once the target image size is calculated.
[root@node1 ~]# o2image /dev/sda1 sda1.out
Copies metadata blocks from /dev/sda1 device to sda1.out file
[root@node1 ~] o2image -I /dev/sda1 sda1.out
Use with CAUTION. Copies meta-data blocks from sda1.out onto the
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