On 06/16/2015 06:43 AM, James Hogarth wrote:
On 16 Jun 2015 12:12, "Always Learning" <centos@xxxxxxxxxxx> wrote:
On Tue, 2015-06-16 at 11:30 +0100, John Hodrien wrote:
On Tue, 16 Jun 2015, Always Learning wrote:
ON Centos 5, using GPARTED I created partitions for filing systems
ext3
and ext4. 4 primary and unlimited (except by space) extended
partitions.
That suggests those partitions are not GPT but old fashioned M$DOS
If it is old fashioned MSDOS, you can have four total primary and
extended,
not four primary plus extended. An extended partition then provides a
container for further logical partitions.
Yes you are correct. Maximum 4 primary or maximum 3 primary and 1
extended which is then sub-divided into more partitions.
LUKS provides a UUID, so being encrypted isn't a barrier to having a
UUID.
But my point was M$ DOS partitions, not being GPT partitions, can have
UUIDs. The original poster appeared to suggest that was not possible. He
wrote
Those were filesystem UUIDs not partition UUIDs ...
LUKS physical volume UUIDs, actually. When you create a LUKS logical
volume within that PV, it also has a UUID, and a filesystem within that
LUKS LV will have its own UUID. These are all part of the partition's
_content_. A GPT partition has its own UUID, independent of the
partition's content. An MSDOS partition does not.
LUKS has its own header similar to ext4, lvm, etc headers which has a UUID
in it.
This UUID being associated with the LUKS header indicates it is not a
partition UUID.
A dd of this (or lvm snapshot) to another partition will keep the same UUID.
Indeed. If your version of cryptsetup is new enough (supports the
"--header" option), try doing the luksFormat operation with a detached
header. Now you will find that your LUKS partition no longer has a UUID.
A partition UUID within a GPT table would not be persisted in this manner,
and msdos labeled disks have no concept of this to begin with.
--
Bob Nichols "NOSPAM" is really part of my email address.
Do NOT delete it.
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