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fopdudel

Member

Registered: 2021-02-12

Posts: 17

Suddenly can't target swap partition with UUID; have to use PARTUUID

So I have a 2GiB encrypted swap partition which I set up yesterday according to this guide. I tested it by rebooting and it was working fine as expected.

Today I booted into my laptop and noticed that it failed to load the swap partition. I also noticed that `$ sudo blkid` only showed a `PARTUUID` for my swap partition and no `UUID` as there was yesterday (including yesterday when I successfully booted with my encrypted swap partition mounting as expected).

Why can I no longer target my partition with `UUID`? I mean, changing my `/etc/crypttab` to target with `PARTUUID` fixed the problem and I can now use my swap partition again, but I'm not sure why this happened or if this indicates a bigger problem I need to fix with my system.

Output of `$ sudo blkid`:

/dev/mapper/swap: LABEL="swap" UUID=[uuid] TYPE="swap"
/dev/nvme0n1p3: UUID=[uuid] TYPE="crypto_LUKS" PARTUUID=[partuuid]
/dev/nvme0n1p1: UUID=[uuid] BLOCK_SIZE="512" TYPE="vfat" PARTUUID=[partuuid]
/dev/mapper/root: UUID=[uuid] BLOCK_SIZE="4096" TYPE="ext4"
/dev/nvme0n1p2: PARTUUID=[partuuid]

The relevant part of my `/etc/crypttab`:

# previous line:
#swap         UUID=[uuid]                                    /dev/urandom            swap,cipher=aes-cbc-essiv:sha256,size=256
# try this with PARTUUID to fix boot error???
swap         PARTUUID=[partuuid]                                    /dev/urandom            swap,cipher=aes-cbc-essiv:sha256,size=256

The relevant part of my `/etc/fstab`:

/dev/mapper/swap none swap defaults 0 0

I should reiterate that the commented out crypttab line was working fine yesterday and I confirmed that I had 2GiB of encrypted swap. It's possible I could've updated a package or something? But I'm just not sure what happened.

ua4000

Member

Registered: 2015-10-14

Posts: 492

Re: Suddenly can't target swap partition with UUID; have to use PARTUUID

The linked wiki page does state explicit, not to use UUID - instead use e.g. PARTLABEL.

The next section tells a workaround, how the UUID or LABEL can be still used - but according to your /etc/crypttab printout above you did not follow this either.