[dm-crypt] LUKS on a block device > 2TB: will it work?

[dm-crypt] LUKS on a block device > 2TB: will it work?

[Wolfgang Sailer]

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Dear all!

Question: Will I be able to use a block device >2TB as the target of LUKS?


Background:

I have a setup in which I mdadm-raid5-ed 3 1TB drives into a /dev/mdN of
1.998 TB in size. On this mdadm array I created a LVM, and one of the LVs
living there is 1.2 TB in size (/dev/mapper/VG/LV-LUKS) and serves as a
block-device for LUKS.

I would like to add another 1TB drive to the array and add the additional
space to the LUKS device. My i386 kernel 2.6.24 configuration has LBD
enabled (pushing the usual 2TB limit typical of a 32bit OS to 16TB), so
mdadm should be able to expand the array to 3TB and I believe also LVM2
should be able to use 3TB of space and be able to expand the LV to 2.2TB.

What I am not sure of is whether LUKS can make use of a 2.2TB blockdevice or
if there will be a 2TB limit somewhere due to some
WORD/INT/LONGINT/LONGLONGINT variable somwhere in the LUKS-code.

ext3, again, is able to create filesystems >2TB, so that should be fine.

regards, Wolfgang

- -- 
Charlie Chaplin hat einmal auf einem
Charlie Chaplin Doppelgänger Wettbewerb
in Monte Carlo den 3. Platz erreicht.















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Re: [dm-crypt] LUKS on a block device > 2TB: will it work?

[Milan Broz]

On 01/02/2010 06:23 PM, Wolfgang Sailer wrote:
> Question: Will I be able to use a block device >2TB as the target of LUKS?

From the kernel block device point of view, there is no difference
between MD, lvm2 or dm-crypt/LUKS device.
You can have stacked LUKS over LVM over MD device of size several TB, it works.
(LUKS just provides key management, there is no block device size limit hardcoded.)

Milan