CSUNIQUE(8) BSD System Manager's Manual CSUNIQUE(8)NAMEcsunique — modify the UUIDs of CoreStorage metadata objects
SYNOPSIScsunique [-v | --verbose] [-n | --dry-run] [-I | --include include]
[-X | --exclude exclude] device ...
DESCRIPTION
The csunique utility can rewrite CoreStorage logical volume group meta‐
data, changing object UUIDs. All CoreStorage objects are uniquely iden‐
tified by UUIDs. This can be useful when copying an initial "canned
image" onto multiple machines to establish these as independent volumes.
The device parameter(s) should be path(s) to the "raw" (character spe‐
cial) disk device(s) such as /dev/rdisk1s1 that constitute the CoreStor‐
age logical volume group. If you specify a "non-raw" (block special)
path such as /dev/disk1s1, or just the disk name such as disk1s1, it will
automatically be converted to the corresponding raw disk device
(/dev/rdisk1s1).
The options are as follows:
-v Output verbose progress information of each step and
the UUID re-mappings.
-n Operates in "dry run" mode; no changes are made to the
on-disk data.
-I Specifies an additional class of UUID objects that
should be modified.
-X Specifies a class of UUID objects that should not be
modified. By default all UUIDs will be changed.
The classes of CoreStorage UUID objects that can be included or excluded
from modification by csunique are indicated using the following charac‐
ters:
f logical volume family (LVF)
g logical volume group (LVG)
l logical volume (LV)
p physical volume (PV)
w MLV wipekey
csunique processes/transforms the CoreStorage metadata in a number of
steps:
1. Firstly, an initial fsck_cs is performed to ensure the source
structure is consistent;
2. If the LVG is currently live and mounted by the kext it is
temporarily "frozen";
3. If the disk partitions are of type Apple_CoreStorage then they
are switched offline (which dissociates the kext from the old
metadata);
4. The CoreStorage metadata is locally parsed and loaded;
5. All object UUIDs are located, and new UUIDs generated for
classes as set by the -I and -X options;
6. UUIDs are re-written to disk;
7. A post-modification fsck_cs is performed to ensure the final
structure is consistent;
8. Finally, any disk partitions taken offline are restored to
Apple_CoreStorage (which will reload the kext with the new
UUID metadata).
DIAGNOSTICS
The csunique utility exits with 0 if the CoreStorage logical volume group
was modified as directed, and with >0 if it was unable to do so. Any
error message is written to stderr.
BUGScsunique cannot modify the LVF UUID if there are any encrypted LVs inside
it. Any mounted LVs must be manually unmounted before invocation.
HISTORY
The csunique utility first appeared in Mac OS X 10.8.1.
Darwin September 25, 2012 Darwin
