I was checking the users in my unix box. Some old users where created by the previous administrator. When i tried to delete from the smc it was throwing error, “The account is mandatory, cant be deleted”.

So, There is a workaround.

1. remove the entry from the passwd file # vi /etc/passwd

2. #pwconv

3. cat /etc/shadow

Q. How do I change ip address in Linux?

A. There are different ways to change IP address in Linux
(a) Command Line tools

(b) Modify configuration files

(c) Use GUI tools

Task: Display current IP address and setting for network interface called eth0

Use ifconfig command:
# ifconfig eth0
Output:

eth0      Link encap:Ethernet  HWaddr 00:30:48:5A:BF:46
          <strong>inet addr:<span style="color: rgb(255, 0, 0);">10.5.123.2</span>  Bcast:<span style="color: rgb(153, 102, 51);">10.5.123.63</span>  Mask:<span style="color: rgb(0, 153, 0);">255.255.255.192</span></strong>
          inet6 addr: fe80::230:48ff:fe5a:bf46/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:728204 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1097451 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:62774749 (59.8 MiB)  TX bytes:1584343634 (1.4 GiB)
          Interrupt:177

Task: Change IP address

You can change ip address using ifconfig command itself. To set IP address 192.168.1.5, enter command:
# ifconfig eth0 192.168.1.5 netmask 255.255.255.0 up
# ifconfig eth0


To make permanent changes to IP address you need to edit configuration file according to your Linux distribution.

alias abort=’echo shutdown abort|sqlplus -L -s / as sysdba’

alias alertvi=’vi $ORACLE_HOME/admin/ ORACLE_SID/bdump/alert_ORACLE_SID.log’

alias nomount=’echo startup nomount quiet|sqlplus -L -s / as sysdba’

alias ora=’cd $ORACLE_HOME’

alias pmon=’ps -ef | grep [p]mon’

alias startup=’echo startup quiet|sqlplus -L -s / as sysdba’

alias sysdba=’sqlplus -L / as sysdba’

alias tns=’cd $ORACLE_HOME/network/admin’

alias alert=’tail -100 $ORACLE_LOG/alert_$ORACLE_SID.log|more’

alias blog=’tail -130 /backup/dbbackup.log’

alias bdump=’cd $ORACLE_HOME/admin/sunmoto/bdump’

alias udump=’cd $ORACLE_HOME/admin/sunmoto/udump’

Install a Solaris package

If a package file (i.e., from sunfreeware.com) exists in the current directory, this recipe will allow you to install it on the system.

If the package file is called <packagename>:

pkgadd -d <packagename>

The easiest way to change the default route is to do the following:

1. Use smitty route->Remove Static Route or issue the route -f to flush the routing table.

2. You should see output to the screen informing you that routes are being removed.

3. Then issue the netstat -rn command. You should not see the default in the routing table.

4. Issue the smitty mkroute command. This is pretty straight forward and it will it will add

this default route to the ODM database and make it permanent even after a system reboot.

5. Issue another netstat -rn command, you should see your new default route.

Note : This article is from http://www.linuxconfig.org/Linux_lvm_-_Logical_Volume_Manager

This article describes a basic logic behind a Linux logical volume manager by showing real examples of configuration and usage. Despite the fact that Debian Linux will be used for this tutorial, you can also apply the same command line syntax with other Linux distributions such as Red Hat, Mandriva, SuSe Linux and others.

This is what we are going to do

Create Partitions

For this Linux lvm example you need a unpartitioned hard disk /dev/sdb. First you need to create physical volumes. To do this you need partitions or a whole disk. It is possible to run pvcreate command on /dev/sdb, but I prefer to use partitions and from partitions I later create physical volumes.

Use your preferred partitioning tool to create partitions. In this example I have used cfdisk.

Partitions are ready to use.

Create physical volumes

Use the pvcreate command to create physical volumes.

# pvcreate /dev/sdb1<br /># pvcreate /dev/sdb2<br /></pre> <p>The pvdisplay command displays all physical volumes on your system. </p> <pre># pvdisplay<br /></pre> <p>Alternatively the following command should be used: </p> <pre># pvdisplay /dev/sdb1<br /></pre> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager05.jpg" class="image" title="Create physical volumes with pvcreate"><img alt="Create physical volumes with pvcreate" longdesc="/Image:Logicalvolumemanager05.jpg" src="http://www.linuxconfig.org/images/f/fc/Logicalvolumemanager05.jpg" width="508" height="368" /></a> </dd></dl> <a name="Create_Virtual_Group"></a><h2> <span class="mw-headline">Create Virtual Group</span></h2> <p>At this stage you need to create a virtual group which will serve as a container for your physical volumes. To create a virtual group with the name "mynew_vg" which will include /dev/sdb1 partition, you can issue the following command: </p> <pre># vgcreate mynew_vg /dev/sdb1<br /></pre> <p>To include both partitions at once you can use this command: </p> <pre># vgcreate mynew_vg /dev/sdb1 /dev/sdb2<br /></pre> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager06.jpg" class="image" title="Create Virtual Group"><img alt="Create Virtual Group" longdesc="/Image:Logicalvolumemanager06.jpg" src="http://www.linuxconfig.org/images/0/00/Logicalvolumemanager06.jpg" width="508" height="329" /></a> </dd></dl> <p>Feel free to add new physical volumes to a virtual group by using the vgextend command. </p> <pre># vgextend mynew_vg /dev/sdb2<br /></pre> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager07.jpg" class="image" title="virtual group extend"><img alt="virtual group extend" longdesc="/Image:Logicalvolumemanager07.jpg" src="http://www.linuxconfig.org/images/6/60/Logicalvolumemanager07.jpg" width="508" height="329" /></a> </dd></dl> <a name="Create_Logical_Volumes"></a><h2> <span class="mw-headline">Create Logical Volumes</span></h2> <p>From your big cake (virtual group) you can cut pieces (logical volumes) which are treated as a partitions for your linux system. To create a logical volume, named "vol01", with a size of 400 MB from the virtual group "mynew_vg" use the following command: </p> <ul><li> create a logical volume of size 400 MB -L 400 </li><li> create a logical volume of size 4 GB -L 4G </li></ul> <pre># lvcreate -L 400 -n vol01 mynew_vg<br /></pre> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager08.jpg" class="image" title="Create Logical Volumes"><img alt="Create Logical Volumes" longdesc="/Image:Logicalvolumemanager08.jpg" src="http://www.linuxconfig.org/images/e/e9/Logicalvolumemanager08.jpg" width="508" height="238" /></a> </dd></dl> <p>In this case you have created a logical volume with a size of 1GB and the name of vol02 </p> <pre># lvcreate -L 1000 -n vol02 mynew_vg<br /></pre> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager09.jpg" class="image" title="create logical vol01"><img alt="create logical vol01" longdesc="/Image:Logicalvolumemanager09.jpg" src="http://www.linuxconfig.org/images/a/a0/Logicalvolumemanager09.jpg" width="508" height="420" /></a> </dd></dl> <p>Note the free size in virtual group. </p> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager10.jpg" class="image" title="display virtual group"><img alt="display virtual group" longdesc="/Image:Logicalvolumemanager10.jpg" src="http://www.linuxconfig.org/images/6/6a/Logicalvolumemanager10.jpg" width="508" height="303" /></a> </dd></dl> <a name="Create_File_system_on_logical_volumes"></a><h2> <span class="mw-headline">Create File system on logical volumes</span></h2> <p>The logical volume is almost ready to use. All you need to do is to create a filesystem.: </p> <pre># mkfs.ext3 -m 0 /dev/mynew_vg/vol01<br /></pre> <p>the -m option specifies the percentage reserved for the super-user, set this to 0 if you wish not to waste any space, the default is 5%. </p> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager11.jpg" class="image" title="create file system"><img alt="create file system" longdesc="/Image:Logicalvolumemanager11.jpg" src="http://www.linuxconfig.org/images/4/46/Logicalvolumemanager11.jpg" width="508" height="277" /></a> </dd></dl> <a name="Edit_.2Fetc.2Ffstab"></a><h2> <span class="mw-headline">Edit /etc/fstab</span></h2> <p>Add a entry for your newly created logical volume into /etc/fstab </p> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager12.jpg" class="image" title="edit /etc/fstab"><img alt="edit /etc/fstab" longdesc="/Image:Logicalvolumemanager12.jpg" src="http://www.linuxconfig.org/images/4/45/Logicalvolumemanager12.jpg" width="508" height="277" /></a> </dd></dl> <a name="Mount_logical_volumes"></a><h3> <span class="mw-headline">Mount logical volumes</span></h3> <p>Before you mount do not forget to create a mount point. </p> <pre># mkdir /home/foobar<br /></pre> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager13.jpg" class="image" title="mount logical volumes"><img alt="mount logical volumes" longdesc="/Image:Logicalvolumemanager13.jpg" src="http://www.linuxconfig.org/images/a/ae/Logicalvolumemanager13.jpg" width="508" height="108" /></a> </dd></dl> <a name="Extend_logical_volume"></a><h2> <span class="mw-headline">Extend logical volume</span></h2> <p>The biggest advantage of logical volume manager is that you can extend your logical volumes any time you are running out of the space. To increase the size of a logical volume by another 800 MB you can run this command: </p> <pre># lvextend -L +800 /dev/mynew_vg/vol01<br /></pre> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager14.jpg" class="image" title="Image:logicalvolumemanager14.jpg"><img alt="Image:logicalvolumemanager14.jpg" longdesc="/Image:Logicalvolumemanager14.jpg" src="http://www.linuxconfig.org/images/b/b4/Logicalvolumemanager14.jpg" width="616" height="108" /></a> </dd></dl> <p>The command above does not actually increase the physical size of volume, to do that you need to: </p> <pre># resize2fs  /dev/mynew_vg/vol01<br /></pre> <p>Look at the figure below to see what problems you may encounter when extending a volume: </p> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager15.jpg" class="image" title="extend logical volume"><img alt="extend logical volume" longdesc="/Image:Logicalvolumemanager15.jpg" src="http://www.linuxconfig.org/images/6/67/Logicalvolumemanager15.jpg" width="616" height="537" /></a> </dd></dl> <a name="Remove_logical_volume"></a><h2> <span class="mw-headline">Remove logical volume</span></h2> <p>The command lvremove can be used to remove logical volumes. Make sure that before you attempt to remove logical volumes your logical volume does not have any valuable data stored on it, moreover make sure the volume is unmounted. </p> <pre># lvdisplay<br /></pre> <dl><dd><a href="http://www.linuxconfig.org/Image:Logicalvolumemanager16.jpg" class="image" title="display volume group"><img alt="display volume group" longdesc="/Image:Logicalvolumemanager16.jpg" src="http://www.linuxconfig.org/images/b/ba/Logicalvolumemanager16.jpg" width="616" height="394" /></a> </dd></dl> <pre># lvremove /dev/mynew_vg/vol02<br />

Other Topics

Discussion

Alexander.Orlov 10:35, 30 August 2007 (CDT) Any scenario ideas how/if/why LVM can be combined with GFS or OCFS? Will LVM become obsolete when the networks are fast enough to carry large amounts of data?

A FAQ list for the tutorial

• Is it possible/advisable to use LVM volumes as swap?
• Is it possible and/or advisable to use LVMs for external USB storage devices used for backups?
• Whether it is a good idea to use encrypted LVM volumes; especially encrypted LVM software containing volumes.

I have no answers to these questions yet. Alexander.Orlov 10:35, 30 August 2007 (CDT)

External Links

• Linux Documentation Project-HowTo

Technorati Tags: LINUX LVM

< Querying the RPM database >

As
you already know, the RPM database contains a list of all installed RPM
packages on your system. You can query this database to get info of the
packages on your Linux system. To query a single package, you use the -q option. For example, to query a package whose name is “software”:
# rpm -q software

After issuing this command, rpm either tells you the version of the package, or that the package isn’t installed.

If you want a list of all packages installed on your system, you’ll have to query all with -qa:
# rpm -qa

Most likely this list will be very long, so you’ll need a way to scroll it. The best way is to pipe the list to less:
# rpm -qa | less

If you’re looking for packages whose names contain a specific word, you can use grep
for finding those packages. For example, to get a list of all installed
RPM packages whose names contain the word “kde”, you could do something
like this:
# rpm -qa | grep kde

The above command makes rpm list all packages in its database and pass the list to grep. Then grep checks every line for “kde” and finally shows you all the lines that contain the word “kde”.

Raw Devices on RHEL 5 or OEL 5

Be aware that raw device technology had been deprecated in RedHat Linux 5 (RHEL5) and Oracle Enterprise Linux 5 OEL5). / Linux Kernel 2.6
Does this mean we cannot use Rawdevices in RHEL5 or OEL5? As always there’s a workaround to make this happen by means of UDEV technique and Oracle 11g & 10gR2 has options to configure components to access the block devices directly instead of rawdevices.Before we jump into the workaround, let see what exactly is missing at the O/S level w.r.to rawdevices in RHEL5 and OEL5,

1. /etc/sysconfig/rawdevices file doesn’t exist
2. /dev/raw doesn’t exist.
3. Service by the name “rawdevices” doesn’t exist.

Trying to run the command “service rawdevices restart” will result in “rawdevices: unrecognized service”.

Now lets see an example of configuring rawdevices in RHEL4 and RHEL5.

RHEL4

To map a rawdevice to a block device /dev/sdf1

Step 1: Make an entry in /etc/sysconfig/rawdevices file

/dev/raw/raw1 /dev/sdf1

Step 2: For the mapping to have immediate effect, restart the rawdevices service.

$>service rawdevices restart

Step 3: Change ownership to oracle user

$>chown oracle:dba /dev/raw/raw1

RHEL5 / OEL5

Step 1: Make an entry in /etc/udev/rules.d/60-raw.rules or create your own file viz., /etc/udev/rules.d/<any_no_above_60>-oracle-raw.rules (eg. 63-oracle-raw.rules)

ACTION==”add”, KERNEL==”sdf1″, RUN+=”/bin/raw /dev/raw/raw1 %N”

Step 2: For the mapping to have immediate effect, run below command

$>/bin/raw /dev/raw/raw1 /dev/sdf1

So if you or your system administrator have plans to upgrade an existing release of RHEL or OEL to RHEL5 / OEL5 or planning to perform a new installation of RAC on RHEL5 / OEL5, wherein rawdevices will be / are used, please do take additional care.

For more information you can refer to following
Metalink notes

RAC FAQ: 220970.1 (look for “What storage option should I use for RAC 10g on Linux? ASM / OCFS / Raw Devices / Block Devices / Ext3 ?”)
How to map raw device on RHEL5 and OEL5 – Note 443996.1
Linux 2.6 Kernel Deprecation Of Raw Devices – Note:357492.1
How to install Oracle Clusterware with shared storage on block devices – Note:401132.1

Blogs / Forums
http://frits.homelinux.com/wordpress/?p=27 – Thanks to Frits Hoogland for sharing this information and also for the article on configuring 11g with ASM on CentOS on VMware.
http://www.webservertalk.com/archive221-2007-5-1884747.html – Thanks to Rupan for the explanation on Rawdevices and Block Devices.

Technorati Tags: RAC VMWARE LINUX