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Andrew
Asked: 2019-09-24 17:46:32 +0800 CST

`blkid` shows two swaps, but I only have one in `/etc/fstab`

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I just encrypted my swap file and now after a reboot I see two devices with "swap" listed when I run blkid:

/dev/loop0: UUID="82a141ee-b1fd-4d52-a1fb-c0690bed732e" TYPE="swap"
/dev/mapper/cryptswap1: UUID="3c73ab32-331e-47e7-8cb9-79f82ab41f5d" TYPE="swap"

Does this mean I have two swap files, one encrypted and one not, or is this normal with encrypted swap?

My /etc/fstab only lists one:

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
# / was on /dev/nvme0n1p2 during installation
UUID=6135b409-f997-4289-895e-a0abb0617c2b /               ext4    errors=remount-ro 0       1
# /boot/efi was on /dev/nvme0n1p1 during installation
UUID=757B-FF35  /boot/efi       vfat    umask=0077      0       1
#/swapfile none            swap    sw              0       0
/dev/mapper/cryptswap1 none swap sw 0 0

As does my /etc/crypttab:

# <target name> <source device>         <key file>      <options>
cryptswap1 /swapfile /dev/urandom swap,offset=1024,cipher=aes-xts-plain64

And fdisk -lu lists them both as having 4GiB:

Disk /dev/loop0: 4 GiB, 4294967296 bytes, 8388608 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

Disk /dev/mapper/cryptswap1: 4 GiB, 4294443008 bytes, 8387584 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
swap

0 Answers