Failsafe

Intro

Failsafe is the short name for the RAM bootable rescue image for APF boards (APF6 & OPOS6UL only for the moment). It is a Linux kernel + minimal initrd image all packed together in a standard kernel image (apf6-linux.bin or opos6ul-linux.bin).

Installation

Generate it

$ make apf6failsafe_defconfig      or     $ make opos6ulfailsafe_defconfig
$ make
$ cp buildroot/output/images/*-linux.bin /tftpboot/

Launch it

BIOS> run ramboot

Cool stuff that can be done with it

apf-config

# apf-config

• check eMMC filesystem

Backup eMMC

• you need a network connection with a server that can receive the backup (for example with NFS, here mounted on /mnt/nfs/):

# dd if=/dev/mmcblk2 bs=512 count=7733248 conv=noerror,sync | pv | gzip -c -9 > /mnt/nfs/emmc.bak.gz

• wait some minutes until backup is done ;-)

Restore eMMC from backup

• same principle:

# gunzip -c /mnt/nfs/emmc.bak.gz | pv | dd of=/dev/mmcblk2 conv=sync,noerror bs=512 count=7733248

Backup rootfs partition only

• Check that you are using the right partition ;-) and be sure that it has no errors (here example for OPOS6UL(NANO)):

# dumpe2fs -h /dev/mmcblk0p2 | grep name
# e2fsck /dev/mmcblk0p2 

• Mount rootfs in a temporary mount point:

# mkdir -p /tmp/mnt/rootfs
# mount /dev/mmcblk0p2 /tmp/mnt/rootfs/

• eventually get current date:

# udhcpc -i eth0
# ntpd -nqp 217.147.208.1
# DATE=`date +%Y.%m.%H-%M`

• backup will be put on HOME partition so check there is enough space:

# df -h

• and launch backup:

# cd /tmp/mnt/rootfs/; tar cvzf /home/rootfs_$DATE.backup.tar.gz *

Restore rootfs partition only

• erase current content of rootfs, you will loose all data !!:

# mkfs.ext4 /dev/mmcblk0p2 

• mount rootfs in a temporary mount point:

# mkdir -p /tmp/mnt/rootfs
# mount /dev/mmcblk0p2 /tmp/mnt/rootfs/

• launch restore:

# tar zxvf /home/rootfs_xxx.backup.tar.gz -C /tmp/mnt/rootfs/
# sync
# umount /tmp/mnt/rootfs/
* that's it !