LVM Management in HPUX

Create a LUN from storage and present to the server on which you want to assign a new mount point. To detect new LUN on the server use below command, it will show you all disks presented to the server till now.

#ioscan –fnNC disk

Here:

f:- Generate a full listing, displaying the module's class, instance number, hardware path, driver,  software state, hardware type, and a brief description.

n:- Generate a full listing, displaying the module's class, instance number, hardware path, driver, software state, hardware type, and a brief description.

C:- strict the output listing to those devices belonging to the specified class. 

N:- Display the agile view of the system hardware.

Below command shows the difference between persistent DFS and Legacy DSF. In next steps we are going to use persistent DSF.

#ioscan –m dsf

Persistent DSF           Legacy DSF(s) ======================================== /dev/pt/pt4                         /dev/rscsi/c0t0d0                                           /dev/rscsi/c2t0d0                                           /dev/rscsi/c4t0d0                                           /dev/rscsi/c6t0d0 /dev/rdisk/disk41             /dev/rdsk/c1t0d0                                           /dev/rdsk/c3t0d0                                                           /dev/rdsk/c5t0d0                                           /dev/rdsk/c7t0d0 /dev/rdisk/disk42              /dev/rdsk/c1t0d1                                           /dev/rdsk/c3t0d1                                           /dev/rdsk/c5t0d1                                           /dev/rdsk/c7t0d1

 To find which disks are not used in the LVM.

 #pvdisplay –l  /dev/disk/*

/dev/disk/disk41:LVM_Disk=no /dev/disk/disk42:LVM_Disk=yes /dev/disk/disk43:LVM_Disk=yes /dev/disk/disk44:LVM_Disk=yes /dev/disk/disk45:LVM_Disk=yes

From the above output we are able to find disk41 is not used in LVM. So we proceed with disk41. And cross check with the size of disk.

#diskinfo /dev/rdisk/disk41

SCSI describe of /dev/rdisk/disk41:              vendor: HP          product id: OPEN-V                type: direct access                size: 56691712 Kbytes    bytes per sector: 512

Output suggests that it is the same size of disk for which we are looking for. So proceed to next step.

Create Physical volume(PV)

A disk has to be initialized before LVM can use it.

#pvcreate /dev/rdisk/disk41

Physical volume "/dev/rdisk/disk41" has been successfully created.

 If disk41 already initialized before then you will get below error message

# pvcreate: The Physical Volume already belongs to a Volume Group

If you are sure the disk is free you can force the initialization using the -f option:

#pvcreate –f /dev/rdisk/disk41

Create Volume Group(VG)

Select a unique minor number for the VG:

# ll /dev/*/group

crw-r--r-- 1 root sys 64 0x000000 Apr 4 2010 /dev/vg00/group crw-r--r-- 1 root sys 64 0x010000 Oct 26 15:52 /dev/vg01/group crw-r--r-- 1 root sys 64 0x020000 Aug 2 15:49 /dev/vg02/group

Create the VG control file (group file):

# mkdir /dev/vg03

# mknod /dev/vg03/group c 64 0x030000

Create the VG

#vgcreate  -s 256 /dev/vg03 /dev/disk/disk41

Volume group "/dev/vg03" has been successfully created. Volume Group configuration for /dev/vg03 has been saved in /etc/lvmconf/vg03.conf

 s: Size of physical extend(PE) in MB.

If you have 2 or more PV to add in a VG, you can add them in one go, just adding next to disk41 with a space.

#vgcreate –s 256 /dev/vg03 /dev/disk/disk41 /dev/disk/disk40

To display VG information

#vgdisplay  -v /dev/vg03

--- Volume groups --- VG Name                           /dev/vg03 VG Write Access                read/write VG Status                           available Max LV                             255 Cur LV                              1 Open LV                           1 Max PV                             16 Cur PV                              1 Act PV                              1 Max PE per PV                1727 VGDA                               2 PE Size (Mbytes)             256 Total PE                           216 Alloc PE                           0 Free PE                            216 Total PVG                         0 Total Spare PVs                0 Total Spare PVs in use      0 VG Version                       1.0 VG Max Size                    6908g VG Max Extents               27632

Create Logical Volume(LV)

To create a LV from a VG (option: L- assigns Size in MB; l - Assigns size in Number of PE, n – assigns name to LV) 

# lvcreate  -L 55040 –n /dev/vg03/lvol1 /dev/vg03

Logical volume "/dev/vg03/lvol1" has been successfully created with character device "/dev/vg03/lvol1" Logical volume "/dev/vg03/lvol1" has been successfully extended. Volume Group configuration for /dev/vg03 has been saved in /etc/lvmconf/vg03.conf

 To display LV information

# lvdisplay -v /dev/vg03/lvol1

--- Logical volumes --- LV Name                          /dev/vg03/lvol1 VG Name                         /dev/vg03 LV Permission                 read/write LV Status                          available/syncd Mirror copies                    0 Consistency Recovery     MWC Schedule                           parallel LV Size (Mbytes)             55040 Current LE                        215 Allocated PE                     215 Stripes                               0 Stripe Size (Kbytes)          0 Bad block                          on Allocation                         strict IO Timeout (Seconds)      default

Create File system

 You can use newfs to put a FS onto the LV:

# newfs  -F vxfs /dev/vg03/rlvol1

F: - File system type either hfs or vxfs. Nowadays it is always recommended to use a VxFS (=JFS) filesystem.

Mount File system

Mounting created File System

#mkdir /data

#mount /dev/vg03/lvol1 /data

Use the bdf command to see the mounted file systems

#bdf

Entries in /etc/fstab file

Make entries in /etc/fstab file to make mount point permanent between reboots. You can do this with below command or open this file with vi editor and add entries at the end.

# echo “/dev/vg03/lvol1  /data vxfs defaults 0 2” >> /etc/fstab

#vi /etc/fstab

# System /etc/fstab file.  Static information about the file systems # See fstab(4) and sam(1M) for further details on configuring devices. /dev/vg00/lvol3 / vxfs delaylog 0 1 /dev/vg00/lvol1 /stand vxfs tranflush 0 1 /dev/vg00/lvol4 /home vxfs delaylog 0 2 /dev/vg00/lvol5 /opt vxfs delaylog 0 2 /dev/vg00/lvol6 /tmp vxfs delaylog 0 2 /dev/vg00/lvol7 /var vxfs delaylog 0 2 /dev/vg00/lvol8 /usr vxfs delaylog 0 2 /dev/vg03/lvol1 /data vxfs defaults 0 2

RPM Commands

# rpm -ivh  MySQL-client-3.23.57-1.i386.rpm : Command to instatll the software.

# rpm -qa : Command to Query all the softwares installed.
cdrecord-2.01-10.7.el5
bluez-libs-3.7-1.1
setarch-2.0-1.1

# rpm -qa | grep 'cdrecord'

# rpm -q MySQL-client
MySQL-client-3.23.57-1

# rpm -q MySQL
package MySQL is not installed

# rpm -qa --queryformat '%{name-%{version}-%{release} %{size}\n'
cdrecord-2.01-10.7 12324
bluez-libs-3.7-1.1 5634
setarch-2.0-1.1 235563

# rpm -qf /usr/bin/mysqlaccess
MySQL-client-3.23.57-1


# rpm -qdf /usr/bin/mysqlaccess : Documentation

# rpm -qi MySQL-client : Lot of information about an installed pacakge.

# rpm -qip MySQL-client-3.23.57-1.i386.rpm : Information about the package before installation.

# rpm -qlp ovpc-2.1.10.rpm : List all the Files in a Package using rpm -qlp.

# rpm -qsp MySQL-client-3.23.57-1.i386.rpm : State of the files in a package. installed, replaced or normal

# rpm -qRp MySQL-client-3.23.57-1.i386.rpm : List the Dependency Packages using rpm -qRP
/bin/sh
/usr/bin/perl 

Lock/Unlock An Account In HPUX

[root] passwd -s test : Retrive the password attributes for an account.
test PS    10/17/13    0  91

[root]passwd -l test : Lock the account.
test LK    12/26/13    0  91

[root]passwd -d test : Unlock the account.
test NP    12/26/13    0  91

PS : Password Set.
LK : Account Locked.
NP : No Password.

Cache Memory In Linux

Whenever a user process performs a read/write operation to a file. The original file will not be modified.

A copy of the file will be created and stored in a temporary location to facilitate the read/write operation.

The memory (temporary location) called as Cache Memory.

Restart RPC in HPUX

# /sbin/init.d/Rpcd stop
RPC daemon rpcd stopped

# /sbin/init.d/Rpcd start

starting the DCE RPC Daemon
        /opt/dce/sbin/rpcd

Linux LVM Configuration Files

/etc/lvm                : Default lvm directory location
/etc/lvm/backup         : Where the automatic backups go
/etc/lvm/cache          : Persistent filter cache
/etc/lvm/archive        : Where automatic archives go after a volume group change
/var/lock/lvm           : Lock files to prevent metadata corruption
/etc/lvm/lvm.conf       : Main lvm configuration file
$HOME/.lvm              : LVM history

Remove Unmapped/Unzoned LUN In Linux

echo 1 > /sys/block/sdc/device/delete

Changing The Password In Linux Without Prompting

[root@node1 /]# echo -e "password" | (passwd --stdin rajasekar)
Changing password for user rajasekar.
passwd: all authentication tokens updated successfully.
[root@node1 /]#

Identify The Timezone In Linux

[root@node1 rhel5_x86_64]# cat /etc/sysconfig/clock
# The ZONE parameter is only evaluated by system-config-date.
# The timezone of the system is defined by the contents of /etc/localtime.
ZONE="America/New_York"
UTC=true
ARC=false
[root@node1 rhel5_x86_64]#

AIX Disk Mapping To LPAR

First the disk has to presented to the VIOS and then it will presented to the LPAR.

We look first at which VIO the LPAR belongs.

aixlpar01# lsrsrc IBM.ManagementServer
Resource Persistent Attributes for IBM.ManagementServer
resource 1:
        Name             = "10.0.0.1"
        Hostname         = "10.0.0.1"
        ManagerType      = "HMC"
        LocalHostname    = "10.0.0.2"
        ClusterTM        = "9078-160"
        ClusterSNum      = ""
        ActivePeerDomain = ""
        NodeNameList     = {"aixlpar01"}
aixlpar01#


We connect the VIO with padmin and scan the HBA’s.


$ ssh padmin@10.0.0.1
padmin@10.0.0.1's password:
Last unsuccessful login: Wed Dec 19 16:42:17 GMT+01:00 2012 on ssh
Last login: Wed Dec 19 16:42:47 GMT+01:00 2012 on /dev/pts/0

aixvio01$ cfgdev

Some error messages may contain invalid information
for the Virtual I/O Server environment.

Method error (/usr/lib/methods/cfgqlfscsi -l fscsi2 ):
        0514-061 Cannot find a child device.
Method error (/usr/lib/methods/cfgqlfscsi -l fscsi3 ):
        0514-061 Cannot find a child device.
aixvio01$


Now check for free disks:

aixvio01$ lspv -free
NAME            PVID                                SIZE(megabytes)
hdisk5          none                                153600
aixvio01$

hdisk5 is free but no PVID is assigned.

aixvio01$ chdev -dev hdisk5 -attr pv=yes
hdisk5 changed
aixvio01$

Now we need to find to which LPAR we have to assign (make a note of the LPAR ID).

aixvio01$ lssyscfg -r lpar -F lpar_id,name,state
1,aixvio01,Running
2,aixlpar01,Running
3,aixlpar02,Running
5,aixlpar03,Running
aixvio01$

Now assign the disk to the LPAR:

aixvio01$ lsmap -all | grep 0002
vhost3          U7778.23X.106DA2A-V1-C17              0x00000002
aixvio01$

aixvio01$ mkvdev -vdev hdisk5 -vadapter vhost3
vtscsi9 Available
aixvio01$

Run the cfgmgr on the LPAR:

aixlpar01# cfgmgr
aixlpar01# lspv
hdisk0          0006da2a3cdd9771                 rootvg     active
hdisk1          0006da0ab3df2fa6                 None

Linux Interview Question

1) Linux Booting Process.

2) What is swap memory ?

3) What is Multipath ?

4) How to scan a LUN ?

5) How to find WWN of HBA ?

6) How to create a FTP user ?

7) How to build a Kernel ?

8) What is MBR Reset ?

9) How to add a scrpit to default run level ?

10) What is tune2fs ?

Interface Speed Change In Linux

1) cp /etc/sysconfig/network-scripts/ifcfg-eth0 /tmp/

2) vi /etc/sysconfig/network-scripts/ifcfg-eth0

Append following line:
ETHTOOL_OPTS="speed 1000 duplex full autoneg on"

3)/etc/init.d/network restart

Verify the changes:

ethtool eth0

Boot Into On HPUX

HPUX > boot vmunuix : Comman to boot from a kernel.

HPUX > boot -is : Single User Mode: -i# : # Init Level.

HPUX > boot -tm : Tuneable Maintenance Mode (Fail Safe Mode)

HPUX > boot -lm : LVM Maintenance Mode.

HPUX > boot -mv : VxVM Maintenance Mode.

NIC Speed Change on AIX

chdev -l en0 -a state=detach
chdev -l ent0 -a media_speed=1000_Full_Duplex
chdev -l en0 -a state=up
mkdev -l inet0

Command to find the HBA LUN connection details

cd /usr/DynamicLinkManager/bin
./dlnkmgr view -path
./dlnkmgr view -hba
./dlnkmgr view -lu

Step 1: Execute below command to find the offline path id
         
           /usr/DynamicLinkManager/bin/dlnkmgr view -lu
       

Step 2:  Find the offline pathId and execute below command.

          dlnkmgr online -pathid   <pathid>

Step 3:  Execute below command to verify if the path is back online
                       
           /usr/DynamicLinkManager/bin/dlnkmgr view -lu  (or)  /usr/DynamicLinkManager/bin/dlnkmgr view -path

How To fix the timeout Issues on AIX for a User

Put the following in /etc/profile otherwise add it to users $HOME/.profile

TMOUT=10800

(or)
export TMOUT=10800 (the session will be not be closed for 3 (3*60*60) hour)

TIMEOUT=10800 (for bash)
TMOUT=10800 (for ksh)

To Stop/Start the LPD(print Queue) in AIX

stopsrc -s qdaemon
startsrc -s qdaemon

Commnads to start the XManager in AIX

lslpp -l | grep -i x11
export DISPLAY=10.129.4.133:0
xterm
lslpp -l X11.base.lib
exit
ps -ef | grep -i x

Start And Stop A Oracle Cluster

Oracle Cluster Service is called as CRS.

The CRS has to be started using the binary called crsctl.

You have login with the Oracle ID and execute the command:

# crsctl start crs

# crsctl check crs

# crsctl stop crs

Successful start of crs can be seen with the check crs command:

Cluster Synchronization Services appears healthy
Cluster Ready Services appears healthy
Event Manager appears healthy

Uptime Explained

It shows you the system time in 24 hours format.

Numbers of Users Logged In.

Load Average.

While the sequence 0.25, 0.25, 0.19 represent for the past 1 minutes, 5 minutes and 15 minutes.

Check the current attached disks

#cat /proc/scsi/scsi | egrep -i ‘Host:’ | wc -l

#fdisk -l 2>/dev/null | egrep ‘^Disk’ | egrep -v ‘dm-’ | wc -l

LUN Detection in Linux

Before Scanning the LUN, take the output of fdisk-l

Execute the command:

echo "- - -" > /sys/class/scsi_host/host#/scan

host : Refers to the HBA Device Name.

Run the # fdisk -l and look for the newly assigned LUN.

NTP Sync Manually

1. Use the "xntpd -x" command to slowly bring the clocks
into sync. ( +/- 2 seconds per minute )

NOTE: Starting time cannot be more than 1000 seconds
out of sync with the server or the xntpd daemon
will terminate and the error messages referenced
above will be logged to syslog. Also note that
the system's clock is never set BACKWARDS.
Instead, the clock is slowed down and the server
is allowed to catch up.

2. Use the "ntpdate -B" command to adjust the clocks into
sync. ( +/- 20 seconds per minute )

3. Set the time/date manually.

4. Reboot.

HPUX: vxfs fsadm: attempt to resize {} failed with errno 28

Error number 28 means ENOSPC from /usr/include/sys/errno.h
#define ENOSPC          28      /* No space left on device      */


Why is the ENOSPC error while running fsadm even though there is enough free space on the filesystem?

Solution:

NOTE: If a file system is full, busy or too fragmented, the resize operation may fails.

HPUX : stty: : Not a typewriter

If you see the message "stty: : Not a typewriter" while login to the server using SSH.

If means the PTS is exhausted and you have increase the value to PTS.

kmtune -q npty
Parameter             Current Dyn Planned                    Module     Version
===============================================================================
npty                       60  -  60

Linux Dmesg: kernel: Your time source seems to be instable or some driver is hogging interupts

If the Liunx Machine Demsg says:

syslog-ng[5244]: STATS: dropped 0

kernel: warning: many lost ticks.

kernel: Your time source seems to be instable or some driver is hogging interupts

kernel: rip __do_softirq+0x4a/0xd2

Solution:

When network load is very high or time source is instable, these messages will be logged.

If NTP is synchronized to NTP server, these messages can be ignored.

What NTP Command Says?

“+” – Good and a preferred remote peer or server (included by the combine algorithm)

“*” – The remote peer or server presently used as the primary reference;

poll : NTP polls each peer every “poll” seconds.

when : is relative time of last poll.

reach : track of last successful polls, 377 is best.

Delay : is network delay, this is fine

offset : offset between local and peer clock (ms) and it should be low.

jitter : Mean deviation (jitter) in the time reported for that remote peer or server.