System Administration

single user vs maintenance mode

 
rajat
Occasional Advisor

single user vs maintenance mode

HI all

i want to know what is difference between single
user mode and maintenance mode or i can say difference between
hpux -is and hpux -lm
regards
rajat
7 REPLIES 7
Pete Randall
Outstanding Contributor

Re: single user vs maintenance mode

According to the man page for hpux, lvm maintenance mode is single user:

-lm Boot the system in LVM maintenance
mode, configure only the root volume,
and then initiate single user mode.


Pete

Pete
Zeev Schultz
Honored Contributor

Re: single user vs maintenance mode

From somewhere in my files :

The only problems that would require booting to Maintenance Mode are
those which prevent the system from booting. For example, if a root volume
group contained three disks, one corrupt and was removed the system, the system
will still boot fine from 1st disk. You need to boot your system into LVM
Maintenance mode to correct a problem with your computer's logical volumes
and/or volume groups. In these cases, the system should be booted
to Maintenance Mode, the boot problem fixed (typically vgcfgrestore), and the
system rebooted fully or to single-user mode so that other LVM configuration
issues can be dealt with, if necessary. Thus LVM maintenance mode boots should
only be done for recovery purposes, when it is not possible to boot in
multi-user or single-user mode.

Regards,

Zeev
So computers don't think yet. At least not chess computers. - Seymour Cray
Uday_S_Ankolekar
Honored Contributor

Re: single user vs maintenance mode

The following DOC has good source of infomations about several booting method.
If you are not abel to view this link then let us know

http://www1.itrc.hp.com/service/cki/docDisplay.do?docLocale=en_US&docId=200000066581126

-USA..
Good Luck..
Steven E. Protter
Exalted Contributor

Re: single user vs maintenance mode

Logical volume Maintenence mode is single user mode plus a little additional configuration to handle lvm maintenance.

I've done logical volume mainteance after booting hpux -is without any ill effect.

SEP
Steven E Protter
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
Jdamian
Respected Contributor

Re: single user vs maintenance mode

Maintenance mode (Mm) is a special single-user mode (SUm). The difference is that, in Mm, the VG00 is not activated and root file system is located in boot disk using an alternate method (LVM is not used because VG00 is not activated).

In SUm as well as Normal boot, VG00 is activated and root file system is located according to some fields contained in the LVM header of boot disk (see lvlnboot manual pages). In Mm, instead, root file system is located using /stand/rootconf file. This file contains three fields: the magic number (0xdeadbeef), the disk block number where root file system starts (32 bit length) and the size of root file system (32 bit length).

In your box, try

# xd ???tx4d4 /stand/rootconf

You'll get something similar to:

0000000 deadbeef 10cb60 15000
-559038737 1100640 86016
000000c

Notice that, in Mm, the boot procedure assumes that the root file system is CONTIGUOUS and it all resides in the same disk.
Jdamian
Respected Contributor

Re: single user vs maintenance mode

(some clarifications)

a) the second field in /stand/rootconf is a disk block value. Block disk size is 1024 bytes (1 KB), not 512 bytes.

b) the size of root file system (third field) is given in disk blocks

The maintenance mode is needed when LVM header of boot disk is corrupt or misconfigured.


For more details about /stand/rootconf read '-c' option of lvlnboot command.
Michael Steele_2
Honored Contributor

Re: single user vs maintenance mode

As stated above LVM maintenance mode use /stand/rootconf instead of using the boot disk bootlif. Because of this LVM maintenance mode is good for testing a corrupted bootlif or boot disk during server boot up problems. If you can come up in 'hpux -lm -is' but not 'hpux -is' then your bootlif is corrupt.

Additionally, LVM maintenance mode can cause damage to your core O/S file system if used with 'init 1, init 2 or init 3'. You can't come up to higher run levels with 'hpux -lm -is' you have to reboot..
Support Fatherhood - Stop Family Law