Difference Between Single User Mode & LVM Mainteance Mode

In LVM maintenance mode, the system boots even if the LVM boot disk is unbootable, since it bypasses the BDRA and LABEL file. However, in single-user mode, the boot disk must be bootable. So use maintenance mode if the disk is not bootable.

In single-user mode, vg00 is activated and the root and /stand are mounted. If these cannot be activated and mounted due to a variety of issues, maintenance mode provides you with a solution. It does not activate or mount anything.

Steps to change the hostname on HP-UX:

1.    First run the hostname command to HP-UX server to change the hostname on HP-UX 11i server:

root@hpuxdev:/> hostname hpuxdev11

I am changing hostname on Integrity Itanium rx6600 running HP-UX 11iv2 from hpuxdev to hpuxdev11

2.    Next execute uname command to set the nodename like hostname:

root@hpuxdev:/> uname –S hpuxdev11

Running uname with –S option changes the nodename to required hostname value on HP-UX 11i server

3.    Change network configuration file (netconf) to make the change permanent during reboots. The netconf files exists under /etc/rc.config.d directory on HP-UX servers:

root@hpuxdev:/> cd /etc/rc.config.d/netconf root@netunix6:/etc/rc.config.d> vi netconf

Open the netconf file using vi editor and search for HOSTNAME variable, replace the old hostname value to new hostname value. It is recommended by HP to keep the value enclosed in double quotes (" ")

root@nedunix6:/etc/rc.config.d> vi netconf HOSTNAME="hpuxdev" OPERATING_SYSTEM=HP-UX LOOPBACK_ADDRESS=127.0.0.1

After changing the HOSTNAME , the netconf file portion with HOSTNAME directives looks like this :

root@nedunix6:/etc/rc.config.d> vi netconf HOSTNAME="hpuxdev11" OPERATING_SYSTEM=HP-UX LOOPBACK_ADDRESS=127.0.0.1

5.Restart the network configuration settings on HP-UX server by running following command .Make sure you run these command from the CONSOLE or MP (Management processor) , sometimes we have noticed network timeout for few seconds while restarting network settings :

root@hpuxdev:/> /sbin/init.d/net start

Verify changes hostname on HP-UX:

Finally run following commands to make sure hostname and nodename is changed to newer name:

root@hpuxdev:/> hostname hpuxdev11 root@hpuxdev:/> nodename hpuxdev11

Configuring a GSP LAN Console

From the GSP Prompt
GSP> SO: Security options & access control
Do you want to modify the GSP wide parameters? - reply N
Do you want to modify the user number 1 parameters? reply Y
Enter new User's Name: admin
Confirm entry:
Current Organization's Name is:
Do you want to modify it? - Reply N
Enter new Login: admin
Enter new Login for confirmation: admin
Do you want to modify the current password? - Reply Y
Enter new Password: admins
Enter new Password for confirmation: admins
Current Dial-back configuration is: Should be "Disabled"
Do you want to modify it? - Reply N
Do you want to modify the user number 2 parameters? - Reply Q
GSP> LC: Configure LAN console
Set the IP address to the Lan Console IP assigned.
Set the GSP Host Name the same as the system's name. ex: crusher (not crusher-c)
Set the Subnet Mask - 255.255.255..0
Set the Gateway address - same as system's primary IP
GSP> ER: Enable remote or LAN console
Current console access state is: Should be
   Remote Console: Enabled
   LAN Console: Enabled

Difference between Paging & Swapping

"Swapping" actually refers to an old(er) memory management mechanism wherein all "pages" of a process where rolled-out to disk when memory needed to be freed.

"Paging" is the modern, more sophisticated mechanism wherein pages of memory are aged over time and so moved to disk as they become unused. Paging imposes much less overhead than the all-or-none swapping.

In HP-UX, you have "swap" space, but in the modern versions HP is doing paging, using the swap space.

Process of paging and swapping are interchangeably used.

But there is a difference between then:

1. Paging : Is the process of removing only one page from virtual space into physical memory and this is called "Page in", and removing only one page from physical memory into the virtual space and this is called "page out".

2. Swapping: Is the process of removing all of a process's pages from physical memory to virtual space and called "Swap out", and removing all of a process's pages from virtual space to physical memory and it is called "Swap in".

Conclusion:

Paging: Only one page.

Swapping: the entire pages belonging to a process.

Locating the disk in Rack

A Simple way of locating a disk is to issue the following command, and watch which disk’s access light illuminates.

# dd if=/dev/rdsk/disk_in_question of=/dev/null

How to find the Bad diks

1. Check the syslog (/var/adm/syslog/syslog.log) looking for disk errors.
2. Check the ioscan (ioscan -fnC disk), looking for NO_HW rather than Claimed.
3.  If diaglogd is running then check STM logs (/var/opt/resmon/log/event.log)
4.  Check the volume group to see if the disk is listed and whether there is any problem with it's status (vgdisplay -v | more)
5. Check lvmtab to see if the disk is supposed to be in a volume group (strings /etc/lvmtab | more)