Many Ubuntu Server administrators have encountered this frustrating scenario: after a fresh installation, the system hangs indefinitely during boot with the message:

Adding 524284k swap on /dev/mapper/test--vg-swap_1. Priority:-1 extents:1 across:524284k

While the recovery mode workaround exists (dropping to recovery and resuming normal boot), this isn't a sustainable solution for production environments.

The issue typically stems from LVM (Logical Volume Manager) configuration problems during swap space initialization. Several factors can contribute:

• Incorrect UUID mapping in /etc/fstab
• Missing or corrupt swap signature
• Race conditions in device initialization
• Filesystem check failures on LVM volumes

First, verify your current swap configuration:

sudo swapon --show
sudo blkid | grep swap
sudo cat /proc/swaps

Check your fstab entries:

sudo cat /etc/fstab | grep swap

Option 1: Reinitialize Swap Space

sudo swapoff -a
sudo mkswap /dev/mapper/test--vg-swap_1
sudo swapon /dev/mapper/test--vg-swap_1

Then update fstab with the new UUID:

sudo nano /etc/fstab

Option 2: Modify Systemd Swapon Service

Create an override file to add dependencies:

sudo systemctl edit dev-mapper-test\x2d\x2dvg\x2dswap_1.swap

Add these lines:

[Unit]
After=systemd-udev-settle.service
After=lvm2-activation.service

Edit your grub configuration:

sudo nano /etc/default/grub

Add to GRUB_CMDLINE_LINUX_DEFAULT:

resume=/dev/mapper/test--vg-swap_1 noresume

Update grub and reboot:

sudo update-grub
sudo reboot

Post-reboot, verify the swap is active:

free -h
lsblk -f
systemctl status dev-mapper-test\\x2d\\x2dvg\\x2dswap_1.swap

Check dmesg for swap-related messages:

sudo dmesg | grep -i swap

Remember to test these solutions in a staging environment before applying to production systems. The exact approach may vary based on your specific LVM configuration and Ubuntu Server version.

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Recently while deploying a fresh Ubuntu Server 22.04 LTS instance, I encountered an unusual boot hang during system initialization. The system would consistently freeze at:

[   3.451236] Adding 524284k swap on /dev/mapper/test--vg-swap_1. Priority:-1 extents:1 across:524284k

Interestingly, booting into recovery mode and selecting "Resume normal boot" would bypass the issue, suggesting this is specifically related to swap activation during early boot.

After examining the LVM setup, here's what I found in /etc/fstab:

/dev/mapper/test--vg-swap_1 none swap sw 0 0

And the corresponding output from lvdisplay:

--- Logical volume ---
LV Path                /dev/test-vg/swap_1
LV Name                swap_1
VG Name                test-vg
LV UUID                xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
LV Write Access        read/write
LV Creation host, time ubuntu-server, 2023-08-15 14:32:15 +0000
LV Status              available
# open                 0
LV Size                512.00 MiB
Current LE             128
Segments               1
Allocation             inherit
Read ahead sectors     auto
- currently set to     256
Block device           253:1

Temporary solution was to edit grub and add noswap to boot parameters, but this wasn't ideal for production. After deeper investigation, I discovered the system was trying to activate swap before the LVM devices were fully available.

Here's how I modified the boot sequence:

# First, backup the original initramfs
sudo cp /boot/initrd.img-$(uname -r) /boot/initrd.img-$(uname -r).bak

# Then update it with proper LVM hooks
sudo update-initramfs -u -k all

The root cause was missing LVM dependencies in the initramfs. Here's the complete fix procedure:

1. Edit the LVM configuration:

sudo nano /etc/lvm/lvm.conf

Find and uncomment or add:

use_lvmetad = 0

2. Rebuild the initramfs:

sudo update-initramfs -u

3. Update grub:

sudo update-grub

After applying these changes, verify the boot process:

# Check initramfs contents
lsinitramfs /boot/initrd.img-$(uname -r) | grep lvm

# Test the new configuration
sudo systemctl daemon-reload
sudo systemctl restart lvm2-lvmetad.service

For more reliable swap activation, consider using UUID instead of device mapper path. First find your swap UUID:

sudo blkid /dev/mapper/test--vg-swap_1

Then modify /etc/fstab:

# Old entry
# /dev/mapper/test--vg-swap_1 none swap sw 0 0

# New entry
UUID=xxxx-xxxx-xxxx-xxxx-xxxx none swap sw 0 0

Remember to update initramfs after making these changes.