HOWTOs

7. Appendix C. - ide RAID10 with initrd

RAID1 over striped RAID0 pair.... the disks in the RAID0 sets are not quite the same size, but close enough.

/dev/md0 is the /boot partition and is autostarted by the kernel
/dev/md1 and /dev/md3 are the two RAID0 sets autostarted by the kernel
/dev/md2 is the root partition and is started by initrd

df
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/md2                118531     76485     35925  68% /
/dev/md0                  1917      1361       457  75% /boot

# ----------------------------

 fdisk -ul /dev/hda

Disk /dev/hda: 4 heads, 46 sectors, 903 cylinders
Units = sectors of 1 * 512 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/hda1            46      4231      2093   fd  Linux raid autodetect
/dev/hda2          4232    166151     80960   fd  Linux raid autodetect

# ----------------------------

 fdisk -ul /dev/hdb

Disk /dev/hdb: 5 heads, 17 sectors, 981 cylinders
Units = sectors of 1 * 512 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/hdb1            17     83384     41684   fd  Linux raid autodetect

# ----------------------------

 fdisk -ul /dev/hdc

Disk /dev/hdc: 7 heads, 17 sectors, 1024 cylinders
Units = sectors of 1 * 512 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/hdc1            17     84013     41998+  fd  Linux raid autodetect
/dev/hdc2         84014    121855     18921   82  Linux swap

# ----------------------------

 fdisk -ul /dev/hdd

Disk /dev/hdd: 4 heads, 46 sectors, 903 cylinders
Units = sectors of 1 * 512 bytes

   Device Boot    Start       End    Blocks   Id  System
/dev/hdd1            46      4231      2093   fd  Linux raid autodetect
/dev/hdd2          4232    166151     80960   fd  Linux raid autodetect

# ----------------------------
                                                         
# raidtab
#
raiddev /dev/md0
        raid-level      1
        nr-raid-disks   2
        persistent-superblock   1
        chunk-size      8
        device          /dev/hda1
        raid-disk       0
        device          /dev/hdd1
        raid-disk       1

raiddev /dev/md1
        raid-level      0
        nr-raid-disks   2
        persistent-superblock   1
        chunk-size      8
        device          /dev/hdd2
        raid-disk       0
        device          /dev/hdb1
        raid-disk       1

raiddev /dev/md2
        raid-level      1
        nr-raid-disks   2
        persistent-superblock   1
        chunk-size      8
        device          /dev/md1
        raid-disk       0
        device          /dev/md3
        raid-disk       1

raiddev /dev/md3
        raid-level      0
        nr-raid-disks   2
        persistent-superblock   1
        chunk-size      8
        device          /dev/hda2
        raid-disk       0
        device          /dev/hdc1
        raid-disk       1

# ----------------------------

contents of linuxrc

 cat linuxrc
#!/bin/sh
# ver 1.02 2-22-00
#
############# really BEGIN 'linuxrc' ###############
#
# mount the proc file system
/bin/mount /proc

# start raid 1 made of raid 0's
/bin/raidstart /dev/md2

# tell the console what's happening
/bin/cat /proc/mdstat

# Everything is fine, let the kernel mount /dev/md2
# tell the kernel to switch to /dev/md2 as the /root device
# The 0x900 value is the device number calculated by:
#  256*major_device_number + minor_device number
echo "/dev/md2 mounted on root"
echo 0x902>/proc/sys/kernel/real-root-dev

# umount /proc to deallocate initrd device ram space
/bin/umount /proc
exit

# ----------------------------

contents of initrd

./bin/ash
./bin/echo
./bin/raidstart
./bin/mount
./bin/umount
./bin/cat
./bin/sh
./dev/tty1
./dev/md0
./dev/md1
./dev/md2
./dev/md3
./dev/md4
./dev/console
./dev/hda
./dev/hda1
./dev/hda2
./dev/hda3
./dev/hdb
./dev/hdb1
./dev/hdb2
./dev/hdb3
./dev/hdc
./dev/hdc1
./dev/hdc2
./dev/hdc3
./dev/hdd
./dev/hdd1
./dev/hdd2
./dev/hdd3
./dev/initrd
./dev/ram0
./dev/ram1
./dev/ram2
./dev/ram3
./dev/ram4
./dev/ram5
./dev/ram6
./dev/ram7
./etc/raidtab
./etc/fstab
./lib/ld-2.1.2.so
./lib/ld-linux.so.1
./lib/ld-linux.so.1.9.9
./lib/ld-linux.so.2
./lib/ld.so
./lib/libc-2.1.2.so
./lib/libc.so.6
./linuxrc
./proc