details on /stand/rootconf

[Jdamian]

Hi

According to my knowledge about the file /stand/rootconf (in HP-UX 11.11), it contains the first disk block (1 block = 1024 bytes) where the root file systems resides and its size.

The length of this file is 12 bytes:
00-03 : deadbeef (magic number)
04-07 : starting block
08-11 : size

# xd -tx4 /stand/rootconf
0000000 deadbeef 14bb60 23000
000000c

This file is rewriten every time the system boots and this info is necessary to boot in maintenance mode.

I wonder what might happen if the root file system is mirrored but its starting block in the mirror disk is different than the "main" disk. I guess the system won't boot in maintenance mode from the mirror disk, will it?

Why does rootconf contain info about just one disk, and not about every root disk in VG00?


These issues appeared recently when I booted a new HP-UX 11.31 server. The rootconf of this new server is larger than 12 bytes -- it is 40 bytes sized.

# xd -v -tx4 /stand/rootconf
0000000 deadbeef 1f8b60 80000 40000003
0000010 0 0 0 0
0000020 0 0
0000028

What are those new fields on this new rootconf?

Thanx in advance

[Ganesan R · Accepted solution]

Hi,

>>>I wonder what might happen if the root file system is mirrored but its starting block in the mirror disk is different than the "main" disk<<<

It cannot be. Because first three logical volumes of vg00(boot,swap,root) should be same as original. You cannot have these lv's somewhere else on the disk like other lv's.

[Jdamian]

really?

[Patrick Wallek]

lvol1, lvol2 and lvol3 in VG00 **MUST** be defined as contiguous LV's, meaning **ALL** extents have to be allocated in one chunk on the disk.

Now, when you create a mirrored root disk, you **MUST** mirror lvol1, lvol2 and lvol3, in that order and before any other LV's in VG00. The first 3 LV's must be first on the disk.

Any LV's in VG00 other than those can be mirrored in any order.

So, to your question -- the boot loader knows where to find the first 3 LV's and **should** know how to find anything it needs. Booting into LVM maintenance from either disk should work fine.

[Torsten.]

Hi Oscar,

more information about /etc/rootconf is here:

http://docs.hp.com/en/B2355-60130/lvlnboot.1M.html

"...
Mirrored root_lv volumes should start at the same offset on each physical volume so that the location stored in /stand/rootconf works for maintenance-mode boots off of any mirror."

[Jdamian]

.