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Re: How to obtain UUID of drives (squeeze udev lacks vol_id)

On 2010-03-21 23:51, Paul E Condon wrote:

On 20100321_181749, Ron Johnson wrote:

On 2010-03-21 17:52, Tom H wrote:

*You* should not need to set the UUID.  It should just magically be
there.
$ /sbin/blkid -t TYPE=swap
/dev/sdb1: TYPE="swap" LABEL="swap1" \
UUID="c69f59ff-b928-4232-b44c-8da0f12c52db"

You can cnahe the UUID of any ext partition with

cnahe???

It is Sunday and my first weekend off in a few weeks so my fingers are
on holiday...



tune2fs -U <uuid> /dev/...

But you're *not* supposed to *need* to,

You do need to do so if you install a second/third/fourth...
distribution or version and mkswap changes the UUID of the swap

I'd want *proof* (i.e., booting into different distros) that
different mkswap invocations generate different UUIDs.



My reading of man mkswap is that if you don't use the -U option, the
program generates a new, random UUID. Debian will change it's own UUID
if you re-execute mkswap on the same partition, and all other distros
are likely to do the same.



Huh, you're right!

$ date && /sbin/blkid -t TYPE=swap
Mon Mar 22 01:59:13 CDT 2010
/dev/sdb1: TYPE="swap" LABEL="swap1" \
                       UUID="c69f59ff-b928-4232-b44c-8da0f12c52db"

# date && mkswap /dev/sdb1
Mon Mar 22 01:59:46 CDT 2010
Setting up swapspace version 1, size = 2000056 KiB
no label, UUID=7adf36e1-ec23-4eac-b49c-5c06c0439a10

$ date && /sbin/blkid -t TYPE=swap
Mon Mar 22 02:00:32 CDT 2010
/dev/sdb1: TYPE="swap" LABEL="swap1" \
                       UUID="7adf36e1-ec23-4eac-b49c-5c06c0439a10"

# mkswap -L foobar /dev/sdb1
Setting up swapspace version 1, size = 2000056 KiB
LABEL=foobar, UUID=25c86597-cdd4-48c9-9543-0d50590848f8

$ date && /sbin/blkid -t TYPE=swap
Mon Mar 22 02:04:49 CDT 2010
/dev/sdb1: TYPE="swap" LABEL="foobar" \
                       UUID="25c86597-cdd4-48c9-9543-0d50590848f8"




partition (although I _think_ that you can use "mkswap -U <uuid>") and
you therefore have to boot without swap from your previous install(s).


Or... use a LABEL.



I don't see a way to apply a label to a swap partition. Where can I
find out about such?



mkswap -L foobar /dev/XXYn


What I'd do is:

# swapoff /dev/XXYn

# mkswap -L foobar /dev/XXYn

# vi /etc/fstab

# vi /mnt/other_distro/etc/fstab

--
"History does not long entrust the care of freedom to the weak
or the timid."  Dwight Eisenhower
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