Mirroring the Root File System

[Mihails Nikitins]

Hello,

I'd like to clear up some details on the topic after making the procedure under HP-UX 10.20 and 11.0.

1. mkboot command

A.

Some Forum members recommend the following command disabling quorum checking.
mkboot -a "hpux -lq (;0)/stand/vmunix"

Unfortunately, I haven't found this option neither in system administration guides, nor in "hpux" man pages.
Where it is documented?

B.

Manuals recommend the following syntax of mkboot command.

HP-UX 11.0
mkboot -a "hpux (;0)/stand/vmunix" /dev/rdsk/c0t3d0

HP-UX 10
mkboot -a "hpux (52.3.0;0)/stand/vmunix" /dev/rdsk/c0t3d0

Is "52.3.0" a hardware address? Is it taken automatically when selecting (;0)? My preinstalled systems have simply "hpux" in AUTO record with no parameters. What parameters are passed to kernel by default in this case?

2. "Managing Systems and Worgroups" for HP-UX 11.0 offers to execute "lvextend -m" in the following sequence: boot, root, swap. In my mind, the only reqirement is to place boot volume first. By default, logical volumes seem to occupy physical extents in the following sequence: boot, swap, root, the rest. I do not see any reason to place swap before root.

3.

Command "lvlnboot -v" shows that dump area does not seem to reside on the second disk.
...
Swap: lvol2 on: /dev/dsk/c1t2d0
/dev/dsk/c2t2d0
Dump: lvol2 on: /dev/dsk/c1t2d0, 0

Is it normal? Command like "lvlnboot -d /dev/vg00/lvol2 " does not make any changes.

4. On HP-UX 11.0 "setboot" shows that alternate path is
the newly mirrored device. On HP-UX 10.20 "setboot" showed old value until I changed it manually by "setboot -a". At the same time "lvlnboot -v" showed something like

Root: lvol3 on: /dev/dsk/c0t5d0
/dev/dsk/c0t8d0
Was it necessary to issue "setboot -a" command?

Thank you in advance for any comments!

[John Palmer · Accepted solution]

Hi,

1A. It's not documented in 'man hpux' but what it does is cause the root volume group to be activated even though a quorum of disks is not present (vgchange -a y -q n vg??). In practice, this is probably only useful if you have only two disks in the VG (boot disk and its mirror). If this is the case and one of them fails then without -lq the root VG cannot be activated and the boot fails.

1B. 'hpux' or 'hpux -lq' is sufficient. Your example 52.3.0 is the hardware address of the required disk. The default is the disk you've booted off. /stand/vmunix is the default kernel.

2. You are correct. Mirror them in the same order that they are on the primary disk.

3. It's normal

4. You will need to run setboot (if only to check that all is correct). The commands that you ran to do the mirroring will not have changed anything. I suspect that your 11.00 server already had the ALT path set to the disk you used as the mirror. New 'L' servers are delivered that way. 'K', 'D' and the like used to come with the ALT path pointing to the CD.

Regards,
John

[CHRIS_ANORUO]

To add to John Palmer's contribution:
Create a physical Volume using pvcreate -B /dev/rdsk/c0t3d0
Add the Physical volume to your existing root volume group: vgextend /dev/vg00 /dev/dsk/c0t3d0
Place boot utilities in the boot area:
mkboot /dev/rdsk/c0t3d0; and add an AUTO file in boot LIF area:
mkboot -a "hpux (10/0.3.0;0)/stand/vmunix" /dev/rdsk/c0t3d0
After this point, I normally mirror /stand before root and swap, reason is that the kernel has to be recognised in this mirroring sequence first.

[Ross Gubler]

pvcreate -B
mkboot
mkboot -a
vgextend
lvextend -m 1
(I use a for loop to extend all lv's in vg...example:
for i in /dev/vg00/lvol*
do
lvextend -m 1 $i
done)

[Dyi-Wu Liu_1]

Here comes what I have tested on mirror root

1. pvcreate -B /dev/rdsk/
2. vgextend /dev/vg00 /dev/dsk/
3. mkboot /dev/dsk/
4. mkboot -a "hpux -lq" /dev/rdsk/
5. lvextend -m 1 /dev/vg00/lvol1 /dev/dsk/
Repeat step 5 for any additional logical volumnes that need to be mirrored.
6. lvlnboot -R

Reboot system, hit escape key to stop autoboot.
Boot system from the second disk to verify it.
Reboot again with autoboot from primary disk.
Job done.

[Samir Mehta]

Addendum to the above mails,

Please do not check mirroring only by booting thru the second disk having the primary disk also in the system. You may remove the disk physically, and boot thru mirror. And also, while the system is sunning, remove the primary and check the system works fine. For the second case, it is necessary to follow a correct procedure to put the disk in place.i.e.replacing mirror disks.

samir