Dealing with constant mdraid device renames that F16 DVD (just like F15 did before it) performs and bugs and oddities of grub2 I’ve decided to rename md devices back to what I created and documented them as. While mdadm docs are quite terse, fellow sysadmin came to the rescue:

# mdadm –assemble /dev/md3  /dev/sd[abcdefghijk]3

given how old my mdraid devices were I had to resort to the oldest syntax possible to get things going.

In the meantime Grub2 decided to go crazy on me (boy, it does remind me LILO in it’s old days). So here’s quick problem-solution combo.

Problem

Since I’ve installed F16 rescue mode renamed /dev/md* devices several times. ugh! Apparently grub2 capability to boot from mdraid devices is not mature enough (or the ways Fedora scripts using it are immature…) to get initial setup. Well, /boot/grub2/grub.cfg can be made to have no reference to real devices – no problem, BUT! Apparently Grub2 stashes someplace /boot’s device name when you perform grub2 install!

Solution

solution is to boot into Fedora DVD’s rescue mode and before allowing it to locate all the disks switch to console 2 (Alt-F2) and:

1. rename all md* devices to what they should be via above trick:

# mdadm –stop /dev/md123
# mdadm –assemble /dev/md2 /dev/sd[ac]2

note how we shut down renamed device md123 and bring it back up as md2 – further inspection via

 # mdadm –examine /dev/sda2 | grep Minor
Preferred Minor : 2

confirms that now stored minor has changed.

2. switch back to Fedora’s rescue screen on console 1 (Alt-F1) and let it look for the installed instance.

3. Now select instance and get into the shell.

4. do the advised:

# chroot /mnt/system

5. make darn sure you record your new MD numbers in /etc/mdadm.conf, one way is to walk through the member devices and do:

# mdadm –examine –scan /dev/sda2 >> /etc/mdadm.conf

6. massage /etc/mdadm.conf into something like:

MAILADDR root
# AUTO +imsm +1.x -all
DEVICE /dev/sda*
DEVICE /dev/sdc*

ARRAY /dev/md2 level=raid1 num-devices=2 UUID=xxxf82e4:6xxxxa0d0:44xxx7c0xxxxa021

7. now we need to firm this up and cut initramfs for it (this will include our new /etc/mdadm.conf). Make sure  /etc/dracut.conf has line with  mdadmconf=”yes” uncommented, then run:

# dracut -f /boot/initramfs-$(uname -r).img $(uname -r)

8. finally we need to make sure grub2 is on board for this:

# grub2-install /dev/sdc

# grub2-install /dev/sda

9. just to be sure re-generate grub.cfg:

grub2-mkconfig -o /boot/grub2/grub.cfg

10. we’re done.

after struggling with HOWTO Forge’s recipe and Fedora’s modification of the same recipe, CentOS provides some helpful info on how to set things up the easy way:

# yum install autofs cifs-utils
# mkdir /mnt/smb

Add this line to /etc/auto.master:

 

/mnt/smb /etc/auto.smb.top

Create /etc/auto.smb.top as:

 

* -fstype=autofs,-Dhost=& file:/etc/auto.smb.sub

Create /etc/auto.smb.sub as (adjust as needed):

 

* -fstype=cifs,credentials=/root/secret.txt,uid=500,gid=100 ://${host}/&

Now you can access by simply typing:

 

# cd /mnt/smb/winbox/getme