Emergency Boot

From Buffalo NAS-Central

[edit] Abstract

This section shows how to create your own "emergency boot" partition. So even if your system has completely crashed, you could run it.

[edit] Prerequisites

You need the Fail Safe Firmware and a memory stick / usb drive.

[edit] here we go

1. Have a clean usb partition and partition it (mfdisk -c /dev/sda) as sda1 (the first usb you put into your terastation is sda). It should have about 371MB. Format it xfs or ext2. Touch the file INIT-SYSBACKUP and reboot. (!!: if it is drive, it is automounted to /mnt/usbdisk1, if it is a stick it is not automounted - I used a stick)

TERASTATION login: myroot
root@TERASTATION:~# mkfs.xfs -f /dev/sda1
meta-data=/dev/sda1              isize=256    agcount=8, agsize=31812 blks
         =                       sectsz=512  
data     =                       bsize=4096   blocks=254490, imaxpct=25
         =                       sunit=0      swidth=0 blks, unwritten=1
naming   =version 2              bsize=4096  
log      =internal log           bsize=4096   blocks=1200, version=1
         =                       sectsz=512   sunit=0 blks
realtime =none                   extsz=65536  blocks=0, rtextents=0
root@TERASTATION:~# mkdir /mnt/sda1
root@TERASTATION:~# mount /dev/sda1 /mnt/sda1
root@TERASTATION:~# touch /mnt/sda1/INIT-SYSBACKUP
root@TERASTATION:~# reboot

2. After booting your system has been copied to your stick. If you touch the file /etc/HD-HTGL-EM, then your system is booted from sda1, bypassing other checks. To have Complete Functionality , some other corrections are neccessary. (See below)

TERASTATION login: myroot
root@TERASTATION:~# mount /dev/sda1 /mnt/sda1
root@TERASTATION:~# cd /mnt/sda1
root@TERASTATION:/mnt/sda1# touch etc/HD-HTGL-EM
root@TERASTATION:/mnt/sda1# vi etc/fstab

# /etc/fstab: static file system information.
#
# <file system> <mount point>   <type>  <options>               <dump>  <pass>
/dev/sda1        /              auto    defaults,noatime                0 0
/dev/md0        /mnt/teraroot   auto    defaults,ro                     0 0
proc            /proc           proc    defaults                        0 0
/dev/hda2       swap            swap    defaults                        0 0
/dev/hdc2       swap            swap    defaults                        0 0
/dev/hde2       swap            swap    defaults                        0 0
/dev/hdg2       swap            swap    defaults                        0 0

root@TERASTATION:/mnt/sda1# mkdir mnt/teraroot
root@TERASTATION:~# reboot

3. After you reboot your system, it boots from stick.

TERASTATION login: myroot
root@TERASTATION:~# mount
/dev/sda1 on / type auto (rw,noatime)
proc on /proc type proc (rw)
/dev/shm on /mnt/ram type tmpfs (rw,mode=1777,size=15m)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/md0 on /mnt/teraroot type xfs (ro)
/dev/md1 on /mnt/array1 type xfs (rw,noatime)
/dev/md2 on /mnt/array2 type xfs (rw,noatime)
/proc/bus/usb on /proc/bus/usb type usbdevfs (rw)

Do not worry, if the power led blinks yellow after booting, this is intended.

[edit] Complete Functionality

To have terastation check your disks (and blinking nicely with red LEDs if a disk fails), following conditions must be met:

1. the system partion /dev/md0 must be
   1. built from /dev/hda1 /dev/hdc1 /dev/hde1 /dev/hdg1
   2. up and
   3. mounted (no matter where)
2. the data partitions, e.g. raid1 /dev/md1 /dev/md2 must also be
   1. built from their intended partitions hd'x'3
   2. up and
   3. mounted

The system can be run from a different location. You e.g. could use the last partition hd'x'4, which is probably used as a 'safety margin' to build /dev/md3.

How-to courtesy of André [1]