[dm-crypt] (More) Questions about LUKS / LVM

Milan Broz mbroz at redhat.com
Tue Sep 20 16:52:42 CEST 2011


On 09/20/2011 04:14 PM, Arno Wagner wrote:
> Seems to me the kernel folks are not happy woth the > 0.90 
> formats either or autodetection would work for them.
> 
> No idea what I am going to to when I hit the 2TB size 
> restriction on the 0.90 metadata format, but that will still
> be a while. 

The real problem (and IMHO this caused several LUKS overwrites recently)
is that sometimes it is impossible to distinguish if it is partition or
the whole device it is referring. See mdadm man page:

| 0.90 format superblock.
| This format limits arrays to 28 component devices and limits
| component devices of levels 1 and  greater  to  2  terabytes.
| It  is  also possible for there to be confusion about whether
| the superblock applies to a whole device or just the last partition,
| if that partition starts on a 64K boundary.

(Unfortunately, seems MD wiki with more precise description is still down
because of the kernel.org/linuxfoundation servers security breach...)

Milan


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