AIX LVM Header file

When we execute LVM Command, we get a numerical value as a result of the execution of the command.

Each value has a meaning in it which describes the nature of the LVM command executed and the outcome.


bash-3.2# exportvg vg01
0516-764 exportvg: The volume group must be varied off before exporting.

Here I am trying to export a volume group, which is an active one and it generates a numerical value as well.

/usr/include/lvm.h : This is the file that contains all the variable declaration for the LVM structures.

Booting Phases of HPUX

The booting process of HP Unix is classified into 5 steps:

1) PDC : Processor Dependent Code.

2) ICL : Initial Controller Load.

3) Loading the kernel.

4) Startup scripts.

5) Console login.

Useful HPUX Administrator Commands

# ioscan -funC : Scans for disk attached to the machine.

# ioscan -funC fc : Scans for FC adapter on the machine.

# ioscan -P health -C disk : Shows health status of all the disk.

# ioscan -funC tape : Scans for tape drive on the machine.

# ioscan -m dsf : Mapping between Persistent DSF and Legacy DSF.

# ioscan -funH <Hardware_Path> : Shows list of devices connected to the hardware path.

# ioscan -m lun : Command show the LUN on the machine.

# ioscan -m lun -h <Hardware_Path> : Mapping between the LUN and the Hardware path.

# ioscan -fn : Shows all the devices on the machine.

# lanscan -aip : Show the all the interfaces MAC and Instance Number.

# lanadmin -g <Instance_Number> : Complete information for a particular Interface.

# linkloop -i <Instance_Number> <MAC> : Check the physical cable connectivity of the interface.

# nwmgr : Starting HPUX 11.30, shows physical connectivity of all the interfaces.

# ioscan -fn | grep -i "no_hw" : Get the devices that are not claimed or not in use.

# strings /etc/lvmtab : Command to get the volume groups created and the physical volumes in it.

# lvlnboot -v : Shows current boot logical volume, swap, dump and root logical volume.

# swapinfo -atm : Information about swap space.

# top : Complete information about the machine.

# glance : Complete information about the machine. Similar to "topas" in AIX.

# vmstat -d 1 5 : Shows virtual memory information with "Disk Performance".

Configuration of Dump Device in Hp Unix

This blog states how to configure Dump device and activate a dump device in HP Unix.

Dump Device refer to an object which plays a vital role during the system crash. On the occurence of a system crash the machine reboots, an image of the system (including hardware and software) will be taken as a dump image and stored in a file system. This information can be used for debugging purpose to analyze the reason for crash.

Steps for configuration:

In HP Unix, by default the paging space is also used as a dump device. "lvol2".

1) The dump device should be a size larger than the size of the RAM.

# dmesg | grep -i physical : Command to get the RAM Size.

2) Create a logical volume of continous allocation and bad block allocation disabled.

# lvcreate -n dump -L 1024 -C y -r n  <Volum_Group_Name> : Command to create a logical volume.

3) Assign the created logical volume as a dump device.

# lvlnboot -d /dev/vg_name/lv_name

4) Verify the dump has been assigned.

# lvlnboot -v

Reboot the machine for the dump to get effective.

Swap Device in HP_Unix

This post mainly deals with the management of swap space in hp unix.

Swap refers to the Virtual space or Paging space as referred according to the UNIX flavour.

Importance of Swap Space has the ability to provide much memory space than the machine has.

The default swap space in hp unix  "/dev/vg#/lvol2".

Logical volume of partition "2" is assigned as default swap space. This space cannot be extended or reduced.

# lvcreate -n <Logical_Volume_Name> -L <Size_of_LV> <Volume_Group_Name> : Command to create a logical volume of desired size.

Swap Space should be twice the size of Physical Memory.

# swapon <Logical_Volume_Name> : Command to assign the the created the logical volume as a swap device.

# swapinfo -dtm : Command to verify the created swap device is created an activated.

Ensure the entry has been  made at "/etc/fstab" for the swap space to persist across the reboot.

/etc/fstab

<Logical_Volume_Name>   "/"   swap   defaults 0 0

How to find the devices attached to the FC Card in AIX and HP-Unix

This post shows the best way to find out the devices connected to the FC - HBA.

AIX:

# lsdev -Cc adapter | grep -i fcs* : Command to get the FC adapters connected to the machine.

The output of the command will show the loction code of the FC "port_number-slot_number". Make a note of the numbers.

# lsdev -Cc disk | grep "##-##" : Command to fetch the device connected to the "port_number-slot_number"

HP-Unix:

# ioscan -funC fc : Command  to get the FC adapters connected to the machine.

Make a note of the device file name for the FC adapter "/dev/fcd or /dev/td" depends on manufacturer.

# /opt/fcms/bin/fcmsutil /dev/fcd# get remote all : Command that returns the devices connected to it.

Priority of a Process in AIX

Process refers to a program under a execution.

Process can be executed on foregroud and background.

Priority of a process executed in foreground is 20.

Priority of a process executed in background is 24.

The priority of process can be changed with the nice command.

The range of priority of a proces is +20 to -19.

Smaller the value favored high.

# vmstat 2 5 : Command executed with the priority value of 20.

# nice -n 5 vmstat 2 5 : Command executed with the priority value of 25+5 = 25 (less favored).

# nice -n -5 vmstat 2 5 : Command executed with the priority value of 20-5 = 15 (high favored).

The process could have priority which can be a fixed or non-fixed (dynamic).

Fixed priority could be assigned to a process using the varible,

retcode=setpri(Process ID, priority value).

# ps -lu <user> : Command shows the priority of all the process owned by the user.