#3542 Issue closed: Unable to Recover via USB + External HDD | error: no server is specified¶

codingwithchristopher opened issue at 2025-12-03 04:19:¶

Requesting support or just a question¶

Unable to Recover via USB + External HDD

Platform¶

Linux x64

Output¶

local.conf:
RESCUE=YES
SERIAL_CONSOLE=""
PRE_RECOVERY_SCRIPT="mount -U 5A92297E9229602D /backup"
OUTPUT=ISO
BACKUP=NETFS
BACKUP_URL=file:///backup/rear
ISO_OUTPUT=/backup

Additional information¶

Hello everyone,

I am attempting to utilize ReaR to backup my Ubuntu (24.04 LTS) server for disaster recovery. I want to utilize an external HDD to store the backup archive, and utilize a USB to mount the recovery ISO.

I created the configuration above (admittedly did use AI) and the backup archive was created along with the ISO, I mounted the ISO to a USB and plugged the USB and external HDD to a laptop to test the recovery.

When I choose the USB to boot from I immediately receive: "error: serial port 'com4' isn't found. Switching to GRUB2 boot menu...'

From the grub menu I select 'Relax-and-Recover (BIOS or UEFI without Secure Boot) and receive:
"Loading kernal /isolinux/kernal... error: no server is specified."

Any input or documentation regarding using a USB + External HDD would be greatly appreciated.

codingwithchristopher commented at 2025-12-03 22:40:¶

Upon further investigation there was no need for me to use a USB and an External HDD as ReaR can just perform all the tasks to the external HDD.

I adjusted the config (/etc/rear/local.conf) to the following:

OUTPUT=USB
BACKUP=NETFS
BACKUP_URL="usb:///dev/disk/by-label/REAR-000"
RESCUE=YES

Then I ran:

rear format /dev/sda
rear mkbackup

This formatted the external HDD and created the backup. All is working as intended now. I'll leave the post up in case another ReaR noob stumbles across the same thing.

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[Export of Github issue for rear/rear.]