mirroring boot disk

[Scott Frye_1]

HP-UX 11.11 We are trying to set up our mirror for the boot disk. vg00 is on both c0t6d0(primary) and c2t6d0(mirror). We ran the mkboot /dev/rdsk/c2t6d0 command. What are our next steps?

[Dave Hutton]

Heres my step list:
-Make both disks ready for LVM. Make c4t5d0 bootable. Example.
# pvcreate -B /dev/rdsk/c4t5d0

# pvcreate /dev/rdsk/c4t4d0

-Add disks to vg00:
# vgextend /dev/vg00 /dev/dsk/c4t5d0 /dev/dsk/c4t4d0

-Make c3t4d0 bootable, add AUTO area to LIF header.
# mkboot /dev/rdsk/c4t5d0

# mkboot -a "hpux -lq (10/4/4.5.0)/stand/vmunix" /dev/rdsk/c4t5d0

-Mirror lvol1 thru lvol8 to /dev/dsk/c4t5d0:
# for i in 1 2 3 4 5 6 7 8

do

lvextend -m 1 /dev/vg00/lvol${i} /dev/dsk/c4t5d0

done

#

-Mirror 2nd swap partition, /dev/vg00/swap2 to c4t4d0:
# lvextend -m 1 /dev/vg00/swap2 /dev/dsk/c4t4d0

[Scott Frye_1]

What exactly is this command "mkboot -a "hpux -lq (10/4/4.5.0)/stand/vmunix" /dev/rdsk/c4t5d0
" and what does it do. I've got a sys admin manual that came with the box. It tells me to run "mkboot -a "hpux (;0)/stand/vmunix" /dev/rdsk/c2t6d0". I have no idea what this does. What is the difference between my command and yours?

[Todd McDaniel_1]

You are assigning "no quorum" so your system will boot of the second disk when the first one failes...and you are giving it a hardware path to look for.

[Todd McDaniel_1]

Forgot one thing... yours doesnt do that... the example with -lq does provide for no quorum to allow your box to reboot...

[Scott Frye_1]

so the hardware path is the path to my mirrored disk? And if my primary fails, all I do not have to do anything special to allow it to boot from my mirror?

[john kingsley]

mkboot -a defines the AUTO file in the LIF area. The system reads this file prior to loading the kernel. It tells the system what utilily will be used to load the kernel ("hpux"), what options to use when loading the kernel ("-lq"), and where the kernel is located ("HW-Path/stand/vmunix")

The "-lq" allows you to boot without a LVM quorum. By default, HP-UX will not activate a volume group unless a quorum of disks is present. This option is required if you have mirrored vg00 with two disks. Without this option, your system will not boot if one of your disks are dead even though they are mirrored.

These boot files are located in your LIF area . They can be listed using the "lifls" command. Also, you can view the contents of your AUTO file by running:
lifcp /dev/rdsk/:AUTO -

[A. Clay Stephenson]

You actually want to run the "-lq" on both boot disks or you actually make the box less likely to boot. Unless the no quorun flag is asserted on both disks, the failure of the mirror will cause the primary not to be bootable either because of lack of quorum within the volume group. As long as -lq is specified on both disks then you will always be able to boot from the primary or the alternate. You should also run the setboot command to set the alternate boot path to your mirror. This will let you talk someone through the boot if necessary much, much more easily --- if required at all.

The good news is that because you are mirrored (and I assume these are hot-plug drives), you can now replace a failed disk (even boot) without ever shutting down.

[john kingsley]

I was just reviewing Dave's procedure. It looks like he left out the last few steps for creating a mirror.

After you finish createing your mirrors (lvextend -m 1 /dev/vg00/lvol..... ), you also need to update the root, boot, primary swap, and dump volumes so they know about the new disk. Start by running:
# lvlnboot -v /dev/vg00
This will show you the current definition.
# lvlnboot -r /dev/vg00/lvol3 /dev/vg00
# lvlnboot -b /dev/vg00/lvol1 /dev/vg00
# lvlnboot -s /dev/vg00/lvol2 /dev/vg00
# lvlnboot -d /dev/vg00/lvol2 /dev/vg00
Now run lvlnboot -v /dev/vg00 again, and you should see that your new disk is listed with the root, boot, swap volumes.

[Geoff Wild · Accepted solution]

Here's a full procedure I use:

Say /dev/dsk/c0t6d0 is the root disk and /dev/dsk/c3t6d0 is the disk you want to make a mirror of.

1. Create a bootable LVM disk to be used for the mirror.
pvcreate -B /dev/rdsk/c3t6d0
2. Add this disk to the current root volume group.
vgextend /dev/vg00 /dev/dsk/c3t6d0
3. Make the new disk a boot disk.
mkboot -l /dev/rdsk/c3t6d0
4. Copy the correct AUTO file into the new LIF area.
mkboot -a "hpux -lq (;0)/vmunix" /dev/rdsk/c3t6d0
5. Mirror the boot, root and primary swap logical volumes to the new
bootable disk. Ensure that all devices in vg00, such as /usr, /swap,
etc., are mirrored.
The following is an example of mirroring the boot logical volume:
lvextend -m 1 /dev/vg00/lvol1 /dev/dsk/c3t6d0
The following is an example of mirroring the primary swap logical
volume:
lvextend -m 1 /dev/vg00/lvol2 /dev/dsk/c3t6d0
The following is an example of mirroring the root logical volume:
lvextend -m 1 /dev/vg00/lvol3 /dev/dsk/c3t6d0
6. Update the boot information contained in the BDRA for the mirror
copies of boot, primary swap and root.
/usr/sbin/lvlnboot -b /dev/vg00/lvol1
/usr/sbin/lvlnboot -s /dev/vg00/lvol2
/usr/sbin/lvlnboot -r /dev/vg00/lvol3
7. Check if the BDRA is correct.
/usr/sbin/lvlnboot -R /dev/vg00
8. Verify that the mirrors were properly created.
lvlnboot -v /dev/vg00
The output of this command is shown in a display like the following:
Boot Definitions for Volume Group /dev/vg00:
Boot Definitions for Volume Group /dev/vg00:
Physical Volumes belonging in Root Volume Group:
/dev/dsk/c0t6d0 (1/0/0/3/0.6.0) -- Boot Disk
/dev/dsk/c3t6d0 (1/0/1/0/0/1/1.6.0) -- Boot Disk
Boot: lvol1 on: /dev/dsk/c0t6d0
/dev/dsk/c3t6d0
Root: lvol3 on: /dev/dsk/c0t6d0
/dev/dsk/c3t6d0
Swap: lvol2 on: /dev/dsk/c0t6d0
/dev/dsk/c3t6d0
Dump: lvol2 on: /dev/dsk/c0t6d0, 0

vgdisplay -v vg00

Then lvextend for all other lvols:

lvextend -m 1 /dev/vg00/lvol4 /dev/dsk/c3t6d0
lvextend -m 1 /dev/vg00/lvol5 /dev/dsk/c3t6d0
lvextend -m 1 /dev/vg00/lvol6 /dev/dsk/c3t6d0
lvextend -m 1 /dev/vg00/lvol7 /dev/dsk/c3t6d0
lvextend -m 1 /dev/vg00/lvol8 /dev/dsk/c3t6d0
lvextend -m 1 /dev/vg00/lvol9 /dev/dsk/c3t6d0
lvextend -m 1 /dev/vg00/lvol10 /dev/dsk/c3t6d0
lvextend -m 1 /dev/vg00/lvol11 /dev/dsk/c3t6d0

I atached as well (in case cut'n'paste messed up).

Rgds...Geoff