Contact UsGet started

Using the Rescue CD recovery and diagnostics disk

Written by
Updated at November 26, 2024

If you are unable to boot the main server OS, you can start the server from the dedicated Rescue CD by SystemRescue, which comes with a set of utilities and is available in the KVM console.

Start the server with Rescue CD

  1. In the management console, select the folder the server belongs to.

  2. In the list of services, select BareMetal.

  3. In the row with the server you need, click and select KVM console.

  4. In the KVM console window, in the top menu, select Media → Virtual Media Wizard... or click the CD icon. In the window that opens:

    1. In the CD/DVD Media1 section, click Browse and select the systemrescue<...>.iso image in the common-iso directory.
    2. Click Connect CD/DVD.
    3. Check the Status section for the Virtual CD 1 device to make sure the Connected To field now indicates the path to the CD image you selected and click Close.

  5. To start the server from the selected Rescue CD image, click Reboot to cdrom in the top-right corner of the KVM console.

  6. Wait for the server to restart and the main SystemRescue menu to load. To select the required menu item, use the up and down arrow keys and press Enter.

    SystemRescue main menu elements

    • Boot SystemRescue using default options

      Launches the SystemRescue recovery interface with default settings.

    • Boot SystemRescue and copy system to RAM (copyram)

      Launches the SystemRescue recovery interface while copying the utilities and OS system files used by SystemRescue to RAM.

    • Boot SystemRescue and verify integrity of the medium (checksum)

      Launches the SystemRescue recovery interface while checking the Rescue CD medium for corruption.

    • Boot SystemRescue using basic display drivers (nomodeset)

      Launches the SystemRescue recovery interface using the basic video driver for the GUI.

    • Boot SystemRescue with serial console (ttyS0,115200n8)

      Launches the SystemRescue recovery interface using the serial console.

    • Boot SystemRescue, do not activate md raid or lvm (nomdlvm)

      Launches the SystemRescue recovery interface without RAID management.

    • Boot a Linux operating system installed on the disk (findroot)

      Boots Linux installed on the server's boot disk.

    • Stop during the boot process before mounting the root filesystem

      Boots the OS installed on the server's boot disk and stops the boot process before mounting the root file system.

    • Boot existing OS

      Boots the OS installed on the server. You can use the Tab key to pre-select the disk and partition number the OS is installed in.

    • Run Memtest86+ (RAM test)

      Runs the Memtest86+ RAM testing utility.

    • Reboot

      Reboots the server.

    • Power Off

      Powers off the server.

Use SystemRescue tools

Use SystemRescue to restore or configure your server:

  1. Start the server with Rescue CD.

  2. In the main SystemRescue menu, select Boot SystemRescue using default options.

  3. After you run SystemRescue, the SystemRescue terminal will be launched in the KVM console. In this terminal, enter Manual.

    You will see the ELinks browser where you can learn about the SystemRescue features and explore its documentation.

    To exit ELinks, press Esc, use the up and down arrow keys to select Exit in the menu, and press Enter. Confirm the exit.

The SystemRescue documentation is also available in the GUI.

  1. Start the server with Rescue CD.

  2. In the main SystemRescue menu, select Boot SystemRescue using default options.

    Running SystemRescue will launch the SystemRescue terminal in the KVM console. Use the terminal to run all the commands below.

  3. Get the label of the partition to mount connected to the server:

    blkid

    Result:

    /dev/md127: LABEL="/" UUID="97e4ad6e-edd9-4574-b4b3-23a86f2a701e" BLOCK_SIZE="4096" TYPE="ext4"
/dev/sdb4: UUID="29395ea9-a41c-c71c-2807-2f5889e52967" UUID_SUB="287cdff0-ba68-6981-f46e-e52e0bf2d799" LABEL="3" TYPE="linux_raid_member" PARTLABEL="primary" PARTUUID="d6ad0b56-8291-4e0b-ad93-85d98e078ecf"
/dev/sdb2: UUID="557a2516-47d1-a676-2cad-fa629a418c1f" UUID_SUB="27dfdf6c-c521-c0f3-e52c-46e2b728c0c1" LABEL="1" TYPE="linux_raid_member" PARTLABEL="primary" PARTUUID="b4483bff-0bb2-4077-a530-b64daa4b6fff"
/dev/sdb3: UUID="20426859-f357-0447-6123-af035e85ca01" UUID_SUB="4dd828b0-4b6d-ea13-a9b9-cbeb5aaa0917" LABEL="2" TYPE="linux_raid_member" PARTLABEL="primary" PARTUUID="8e624512-5665-4c11-aa0b-ecbcdb7b1d7a"
/dev/sdb1: PARTLABEL="primary" PARTUUID="b152360c-3157-482e-9804-36620f654ec1"
/dev/md125: LABEL="/boot" UUID="58a6d4a4-d20a-4125-b52c-f76529a398f4" BLOCK_SIZE="4096" TYPE="ext3"
...
/dev/sda1: PARTLABEL="primary" PARTUUID="1a1c7c88-4cce-429f-984f-1626587626c3"

    For example, the server OS partition has the md127 label. Save this value as you will need it when mounting the disk.

  4. Create a local directory to use as the partition mount point:

    mkdir /mnt/serverdisk

  5. Mount the selected partition by specifying the previously saved label:

    mount /dev/<partition_label> /mnt/serverdisk

  6. Go to the mounted disk:

    cd /mnt/serverdisk

    It houses the directory tree of the server OS:

    ls -l

    Result:

    total 64
lrwxrwxrwx   1 root root     7 Jul  8 10:47 bin -> usr/bin
drwxr-xr-x   4 root root  4096 Oct 23 12:09 boot
drwxr-xr-x  21 root root  4360 Oct 24 05:43 dev
drwxr-xr-x  91 root root  4096 Oct 23 12:09 etc
drwxr-xr-x   2 root root  4096 Apr 18  2022 home
lrwxrwxrwx   1 root root     7 Jul  8 10:47 lib -> usr/lib
lrwxrwxrwx   1 root root     9 Jul  8 10:47 lib32 -> usr/lib32
lrwxrwxrwx   1 root root     9 Jul  8 10:47 lib64 -> usr/lib64
lrwxrwxrwx   1 root root    10 Jul  8 10:47 libx32 -> usr/libx32
drwx------   2 root root 16384 Oct 18 14:33 lost+found
drwxr-xr-x   2 root root  4096 Jul  8 10:47 media
drwxr-xr-x   2 root root  4096 Oct 23 20:08 mnt
drwxr-xr-x   2 root root  4096 Jul  8 10:47 opt
dr-xr-xr-x 482 root root     0 Oct 24 05:43 proc
drwx------   5 root root  4096 Oct 23 12:05 root
drwxr-xr-x  25 root root   800 Oct 24 05:43 run
lrwxrwxrwx   1 root root     8 Jul  8 10:47 sbin -> usr/sbin
drwxr-xr-x   2 root root  4096 Oct 18 14:43 snap
drwxr-xr-x   2 root root  4096 Jul  8 10:47 srv
dr-xr-xr-x  13 root root     0 Oct 24 05:43 sys
drwxrwxrwt  12 root root  4096 Oct 24 05:43 tmp
drwxr-xr-x  14 root root  4096 Jul  8 10:47 usr
drwxr-xr-x  14 root root  4096 Oct 18 14:38 var

  1. Start the server with Rescue CD.

  2. In the main SystemRescue menu, select Boot SystemRescue using default options.

    Running SystemRescue will launch the SystemRescue terminal in the KVM console.

  3. To launch the SystemRescue GUI, run the startx command in the terminal.

    This will open the SystemRescue GUI with a browser, diagnostics and computer management tools, and internet access.

  1. Start the server with Rescue CD.

  2. In the SystemRescue main menu, select Run Memtest86+ (RAM test).

  3. In the Memtest86+ utility window that opens, wait until the RAM is tested for errors.

    To cancel the test and reboot the server, press the Esc key.

See also

Previous
Connecting to a KVM console
Next
Creating a VRF