Recovery mode allows you to directly access the disk of your server.
Recovery mode is available to all Mac Mini dedicated server customers, and is accessed through the Customer Control Panel. Recovery mode allows you to reboot your server into an NFS mounted Linux installation. Once booted, you can mount your server's own file system and carry out repairs or configuration necessary to get your server booting again.
In order to use recovery mode, you will need an SSH key pair, used for authentication. If you do not have one, you can generate one easily using the ssh-keygen command line. This will generate you two files, usually called .ssh/id_dsa and .ssh/id_dsa.pub (although they may have rsa rather than dsa in the file name). You will need to copy and paste the contents of the file ending .pub into the control panel.
For each of your servers, the control panel will provide the following options:
|Service||IP||Boot Mode||Authorized Keys|
ssh-dss AAAAB3NzaC1kc3MAAACBAJ64Uh64nXHhSzlxnLl5kVp6rey nz3TPhP6hcZMvRoLJuQMkpoGsXeHXlM8Jmq2sQSgQ2yOSZjd0M9Wy8X veEVxiK5bkB37ORWmJFvBK1bMbrvLiVkMCMgouY9QpYh33uZ6+yZNTK 8MQQNIzx5mU5QmdYSi+kaH8B0uZO4Z2FrM/AAAAFQD0F571/DqVrAWg Ha2NSed2aHIXrwAAAIAKAHvhPGD0EOJvJFHj+Tz3I+b3YYjESWypdO7 qydlaPqQbvCA0rwnwky+1rMkcJomPUNnF0OpdML55THWkOr5FItIR4D oJm3bFNGmdGl5x2SZbUgmz3GTzLc7GH+CF+6JuyPQdZfOsPCeDmV+FP updm3TqxbdpBPo/RyYDra4txgAAAIEAgZ5+GeRud38GOfrZWJ1JjJBl oF5oLlvCGZfqfL//1jhwwOBHtSOyf7mwVbrbbsTwJi/0H9hwquXf7z+ 5os2/3uR0yCzaFjJRiteyrOGxE5FcOZwcA8Iy9CBIzcbKUnAzW6ovEy HyLY1Xjj36E2ctTGkunso7czKJtR+jRwRLOdI= pete@macbeth
You need to paste your public key (the .pub file) into the Authorized Keys section (as shown above). You can then select the mode that you want your server to boot into. Choose "recovery" for recovery mode, and either "linux" or "OS X" when you want to boot into your normal OS.
Once you have saved your changes to the recovery mode configuration using the Apply button, you should reboot your machine using the Power Cycle button (when switching back from recovery mode to normal boot mode, you can just type reboot -f on the command line, rather than power cycling).
When your server is up in recovery mode, you will be able to log in as root using the ssh key you have just generated. It is very likely that you will get a warning from ssh about the host key of your server having changed. This is expected, and can be safely ignored.
Using recovery mode
To check your disks first you need to see the partition table. To do this you need to use parted.
recovery:~# parted /dev/sda print Disk /ramdisk/dev/sda: 40.0GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name Flags 1 20.5kB 35.7MB 35.7MB fat32 EFI boot 2 35.7MB 455MB 419MB hfs+ Recovery 3 455MB 1399MB 944MB hfs+ OSBoot 4 1399MB 1483MB 83.9MB Media 5 1483MB 1535MB 52.4MB ext3 linux-boot 6 1535MB 39.5GB 37.9GB ext3 linux-root 7 39.5GB 40.0GB 537MB linux-swap linux-swap Information: Don't forget to update /etc/fstab, if necessary.
This tells us where the partitions are so we can check them.
recovery:~# e2fsck /dev/sda5 e2fsck 1.40-WIP (14-Nov-2006) /dev/sda5: recovering journal /dev/sda5: clean, 16/12824 files, 8971/51200 blocks recovery:~# e2fsck /dev/sda6 e2fsck 1.40-WIP (14-Nov-2006) /dev/sda6: recovering journal Clearing orphaned inode 3949937 (uid=0, gid=4, mode=0100640, size=1079) Clearing orphaned inode 3967306 (uid=33, gid=33, mode=0140600, size=0) Clearing orphaned inode 3949904 (uid=0, gid=4, mode=0100640, size=3218) Clearing orphaned inode 3967301 (uid=33, gid=33, mode=0140600, size=0) Clearing orphaned inode 3949917 (uid=0, gid=4, mode=0100640, size=1319) Clearing orphaned inode 3964958 (uid=33, gid=33, mode=0140600, size=0) /dev/sda6: clean, 202333/4636672 files, 3927687/9261665 blocks
We can format the swap partition.
recovery:~# mkswap /dev/sda7 Setting up swapspace version 1, size = 536850 kB no label, UUID=c68eedbe-d405-437d-887b-52b20ed249b8
We can check if the disk thinks that it is broken.
recovery:~# smartctl -d ata -H /dev/sda smartctl version 5.36 [i686-pc-linux-gnu] Copyright (C) 2002-6 Bruce Allen Home page is http://smartmontools.sourceforge.net/ === START OF READ SMART DATA SECTION === SMART overall-health self-assessment test result: PASSED
It can be useful to chroot (change root) into the dedicated server if we need to repair various things. This switches you into an environment very much like your normal server, with your normal root filesystem. Additional packages can be installed, services can be started and tested:
recovery:~# mkdir /mnt/root recovery:~# mount /dev/sda6 /mnt/root # This may not be sda6 - check parted output as above. recovery:~# chroot /mnt/root recovery:/# mount /boot recovery:/# mount /proc
When you're done, you should leave the chroot environment and unmount your filesystem before rebooting:
recovery:~# exit # leave chroot recovery:~# umount /mnt/root # unmount root filesystem
Debian and Ubuntu can both be readily reinstalled from the recovery console.
mount /resources cd /scripts/macmini/intel/partition ./partition cd ../install_debian ./install_debian cd ../install_kernel ./doinstall
mount /resources cd /scripts/macmini/intel/partition ./partition cd ../install_ubuntu ./install_ubuntu cd ../install_kernel ./doinstall
At this time we don't have end-user friendly scripts for installing gentoo,centos or OSX - please contact us if you'd like to reimage with one of these operating systems.
Please note, it is very important to run the partition script that matches your dedicated server platform.
Sometimes recovery mode can fail to start up correctly if there's a few dropped packets while the netboot starts. In this event you'll need to wait a few minutes then power cycle the server again to start another boot attempt. Eventually the server will fall back and try and boot locally from disk which may not work.
Ubuntu LTS requires /dev to be on tmpfs, if you're having trouble booting check that /etc/fstab contains
dev /dev tmpfs rw 0 0
this musn't be present for older versions of Ubuntu, Debian or Centos.