Thursday, 30 April 2015

Setup was unable to create a new system partition or locate an existing system partition - Can't install Windows server 2008 R2

I am trying  to install Windows server 2008 R2 on DELL PowerEdge R620 server, & facing issue.

"We couldn't create a new partition or locate an existing one.  For more information, see the Setup log files."




Resolution:

  1. Set your PC to boot from DVD via BIOS
  2. Put the DVD in and let it load until you get to this screen:
  3. Once at this screen, press: (SHIFT+F10) to get a CMD window

Step by step instruction:



  1. MAKE SURE YOU SELECT THE DRIVE YOUR INSTALLING WINDOWS TO NOT ANOTHER. In the CMD window, type in Each Command and Press <ENTER> Key as follows:

    DiskPart <ENTER>
    list disk <ENTER>
    select disk 0 <ENTER>
    clean <ENTER>
    create partition primary align=1024 <ENTER>
    format fs=ntfs <ENTER> (Will Take a While)
    assign <ENTER>
    active <ENTER>
    exit <ENTER>
    exit <ENTER>
  2. After it completes, exit the INSTALL COMPLETELY and reboot.
  3. Once you are back in, go about installing Windows just DO NOT ALLOW Windows to create a new partition, use the only one there.

Monday, 27 April 2015

How to configure RAID5 in Linux

What is RAID????

RAID stands for Redundant Array of Inexpensive Disks. 
This is a solution where several physical hard disks (One+) are governed by a unit called RAID controller, which turns them into a single, cohesive data storage block.
An example of a RAID configuration would be to take two hard disks, each 1TB in size, and RAID them into a single unit 2TB in size. Another example of RAID would be to take these two disks and write data to each, creating two identical copies of everything.
RAID controllers can be implemented in hardware, which makes the RAID completely transparent to the operating systems running on top of these disks, or it can be implemented in software, which is the case we are interested in.


 ADVANTAGES OF RAID5

  • READ Data Transaction rate of RAID 5 is very fast.
  • RAID-5 have capacity to change the number of devices.
  • It is also capable of changing the size of individual devices.
  • RAID5 can also change the chunk size.
  • It is also capable of changing the layout.
  • WRITE Data Transaction rate is a bit slow because of the parity involved.
  • You can get the redundancy without wasting any disk.
  • We can also convert A 2-drive RAID5  to RAID1 & A 3 or more Drive RAID5 to RAID6.
  • A 4-drive RAID5 can be easily converted to A 6-drive RAID6 if you have 4-drive.
 DISADVANTAGES OF RAID5
  • Raid 5 is a little bit complex due to its configuration and parity
  • Rebuilding takes time because of parity calculation involved in raid.
  • if suppose one disk fails, the data from that disk is calculated with the help of data from other disk as well as parity from other disks, due to which reading becomes slow .
RAID allows an administrator to form an array of several hard drives into one logical drive recognized as one drive by the operating system. It also spreads the data stored over the array of drives to decrease disk access time and accomplish data redundancy. The data redundancy can be used to recover data should one of the hard drives in the array crash.

RAID level 0, or striping,

Means that data is written across all hard drives in the array to accomplish the fast disk performance. No redundancy is used, so the size of the logical RAID drive is equal to the size of all the hard drives in the array. Because there is no redundancy, recovering data from a hard drive crash is not possible through RAID.

RAID level 1, or mirroring,

Means that all data is written to each disk in the array, accomplishing redundancy. The data is “mirrored” on a second drive. This allows for easy recovery should a disk fail. However, it does mean that, for example, if there are two disks in the array, the size for the logical disk is size of the smaller of the two disks because data must be mirrored to the second disk.

RAID level 5

Combines striping and parity. Data is written across all disks as in RAID 0, but parity data is also written to one of the disks. Should a hard drive failure occur, this parity data can be used to recover the data from the failed drive, including while the data is being accessed and the drive is still missing from the array.

RAID level 6

Data is written across all disks as in RAID 5, but two sets of parity data is calculated. Performance is slightly worse than RAID 5 because the extra parity data must be calculated and written to disk. RAID 5 allows for recovery using the parity data if only one drive in the array fails. Because of the dual parity, RAID 6 allows for recovery from the failure of up to two drives in the array.
In real life we never create raid on same hard disk. But its exam and examiner is not going to provide you three separate hard disk so you should be able to create three raid partition on same physical hard disk.
To create raid partition we will use fdisk utility.
Execute fdisk command with -l switch it will show hard disk mount point
[root@localhost`]# fdisk -l

Check the output for hard disk mount point. Use that mount point with fdisk command. My hard disk is mounted in /dev/sda so I am using it with fdisk command. If output of above command is different for you then use that mount point. you should use the proper hard disk option whatever you receive in the output of above command, for example it could be hdd sdb
 [root@localhost`]# fdisk /dev/sda
Create a new partition and assign file type to raid
Command (m for help)n
First cylinder (1543-2610, deaults 1543):
press enter Using deafults value 1543 Last cylender ..............): +100M
linux fdisk commmad create new raid partitions

Now create two more partition repeating the same process don't forget to save with w command.

linux raid partitions
Inform kernel about this change by partprobe commands and verify with fdisk -l commands


fdisk -l linux commands
Okey now you have 3 raid partitions and Linux will treat these partition same as three physical hard disks. You can create raid device with these partitions
Create raid 5 device with these partitions
create raid devices
Now format this newly created md0 raid device

mke2fs linux commands
To use this device you must have specify mount point. we are going to use this raid device on /data directory. So create a /data directory and mount md0 on it.

mount Linux commands
This way will mount temporary. To permanently mount make its entry in /etc/fstab file.

fstab Linux files

At this point you have successfully created a raid device md0 and permanently mounted it on /data. In our next article we would add new hard disk in raid device and remove faulty media from raid devices.

Using cat /proc/mdstat is the fastest, simplest indication of the health and status of the RAID arrays. If there are no RAID arrays on the system, the output of the command would return output like this:

[root@sujeet~]# cat /proc/mdstat 

Personalities :unused devices: <none>

Removing a RAID Device

To remove an existing RAID device, first deactivate it by running the following command as root:
mdadm --stop raid_device
Once deactivated, remove the RAID device itself:
mdadm --remove raid_device
Finally, zero super blocks on all devices that were associated with the particular array:
mdadm --zero-superblock component_device
Example 6.5. Removing a RAID device
Assume the system has an active RAID device, /dev/md3, with the following layout .
~]# mdadm --detail /dev/md3 | tail -n 4
    Number   Major   Minor   RaidDevice State
       0       8        1        0      active sync   /dev/sda1
       1       8       17        1      active sync   /dev/sdb1
       2       8       33        2      active sync   /dev/sdc1
In order to remove this device, first stop it by typing the following at a shell prompt:
~]# mdadm --stop /dev/md3
mdadm: stopped /dev/md3
Once stopped, you can remove the /dev/md3 device by running the following command:
~]# mdadm --remove /dev/md3
Finally, to remove the super blocks from all associated devices, type:
~]# mdadm --zero-superblock /dev/sda1 /dev/sdb1 /dev/sdc1

Thursday, 16 April 2015

warning: user mockbuild does not exist - using root

I am trying to install below rpm but enable to install facing issue.

when i am trying to run a rpm file... i am getting this error massage..

[root@chintels Desktop]# rpm -ivh --force firefox-3.6.11-2.el5.src.rpm

warning: firefox-3.6.11-2.el5.src.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
 
1:firefox                warning: user mockbuild does not exist - using root

warning: group mockbuild does not exist - using root

warning: user mockbuild does not exist - using root

Solution:-

The ‘mock’ module is responsible to build the source RPMs (SRPMs) under a chroot environment
and uses the ‘mockbuild’ user.
If the mockbuild user does not exist while installing the source RPM,
you will receive the ‘Warning: user mockbuild does not exist. using root‘ error message.


In order to fix the warning message, install the ‘mock’ module:

[root@sujeet ~]# useradd -s /sbin/nologin mockbuild
[root@sujeet ~]# cd Desktop/

Once done, you should be able to install the required tool under the mockbuild user.

[root@sujeet Desktop]# rpm -ivh firefox-3.6.11-2.el5.src.rpm

warning: firefox-3.6.11-2.el5.src.rpm: Header V3 DSA signature: NOKEY, key ID 37017186
   1:firefox                ########################################### [100%]



Wednesday, 15 April 2015

How do I uninstall & Install rpm packages

RPM command is used for installing, uninstalling, upgrading, querying, listing, and checking RPM packages on your Linux system.
RPM stands for Red Hat Package Manager.
With root privilege, you can use the rpm command with appropriate options to manage the RPM software packages.
1. Installing a RPM package
When you install a RPM, it checks whether your system is suitable for the software the RPM package contains, figures out where to install the files located inside the rpm package, installs them on your system, and adds that piece of software into its database of installed RPM packages.

The following rpm command installs jre client package.


[root@sujeet ]# rpm -ivh <package-name.rpm>

rpm command and options
  • -i : install a package
  • -v : verbose
  • -h : print hash marks as the package archive is unpacked.

2. Query all the RPM Packages 

You can use rpm command to query all the packages installed in your system.
[root@sujeet ]# rpm -qa <package-name.rpm>
  • -q query operation
  • -a queries all installed packages
To identify whether a particular rpm package is installed on your system, combine rpm and grep command as shown below. Following command checks whether jre package is installed on your system.
[root@sujeet ]# rpm -qa| grep jre*

3. Query a Particular RPM Package

The above example lists all currently installed package. After installation of a package to check the installation, you can query a particular package and verify as shown below.
[root@sujeet ]# rpm -q <package-name.rpm>
Note: To query a package, you should specify the exact package name. If the package name is incorrect, then rpm command will report that the package is not installed.
4. Information about Installed RPM Package 
rpm command provides a lot of information about an installed pacakge using rpm -qi as shown below:
[root@sujeet ]# rpm -qi <package-name.rpm>
[root@sujeet ]# rpm -qip <package-name.rpm>
If you have an RPM file that you would like to install, but want to know more information about it before installing, you can do the following:
  • -i : view information about an rpm
  • -p : specify a package name

5. List all the Files in a Package 

To list the content of a RPM package, use the following command, which will list out the files without extracting into the local directory folder.
[root@sujeet ]# rpm -qlp <package-name.rpm>
  • q : query the rpm file
  • l : list the files in the package
  • p : specify the package name

6. Upgrading a RPM Package

Upgrading a package is similar to installing one, but RPM automatically un-installs existing versions of the package before installing the new one. If an old version of the package is not found, the upgrade option will still install it.
[root@sujeet ]# rpm -Uvh <package-name.rpm>
7. Uninstalling a RPM Package
To remove an installed rpm package using -e as shown below. After uninstallation, you can query using rpm -qa and verify the uninstallation.
[root@sujeet ]# rpm -e <package-name.rpm>

8. Verifying all the RPM Packages

The following command verifies all the installed packages.
[root@sujeet ]# rpm -Va <package-name.rpm>
9. If  your Independence issue than use below commend
  
[root@sujeet ]# rpm -nodeps -Uvh package-name.rpm

Sunday, 12 April 2015

failed to initialize core devices

I have setup RHEL release 5.8 on my computer that I am turning into a Server. I have set up Trixbox, but i would like to also set up some other features for networking and for this I would like to get into X Windows. However every time I do I get "failed to initialise core devices".

OR

X wont start: Failed to initialize core devices.

I am getting an xorg "failed to initialize core devices" error when trying to startx 

after installing ATI drivers and configuring the card with "anti-config".

Have a look below error snap:-







Solution:-


Edit xorg.conf


[root@sujeet~]# vi /etc/X11/xorg.conf

if u have other server with same Linux OS than match both file & if any thing missing than change it.

Original xorg.conf file contained :

[root@sujeet]# cat /etc/X11/xorg.conf

# Xorg configuration created by pyxf86config

Section "ServerLayout"
        Identifier     "Default Layout"
        Screen      0  "Screen0" 0 0
        InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "InputDevice"
        Identifier  "Keyboard0"
        Driver      "kbd"
        Option      "XkbModel" "pc105"
        Option      "XkbLayout" "us"
EndSection

Section "Device"
        Identifier  "Videocard0"
        Driver      "vesa"
EndSection

Section "Screen"
        Identifier "Screen0"
        Device     "Videocard0"
        DefaultDepth     24
        SubSection "Display"
                Viewport   0 0
                Depth     24
        EndSubSection
EndSection


Copy full file contained and past on your error OS platform.
Save it after that restart your OS.

I hope your issue got resolved. 





Thursday, 9 April 2015

Installing Oracle VM Server 3.3.1

Installing Oracle VM Server Steps By Steps

All Oracle VM software can be downloaded from the Oracle Software Delivery Cloud:


You must be a registered user, logged in and have accepted the terms and conditions to download software from the Oracle Software Delivery Cloud.
Software downloads are available as Media Packs, each of which represents a different release of the software. It is recommended that you select the most recent Media Pack to obtain patch updates to the software that you intend to install. Each Media Pack contains a collection of ISOs and Zip archives that are available for download. You can select the components that you require for your deployment and download each of these using your web browser.
Depending on your installation strategy, ISOs and Zip archives may need to be copied to the relevant host or hosts involved in a deployment, or should be placed in shared storage accessible to the systems involved.





Pre-installation Tasks and Requirements

Before you start the Oracle VM Server installation, make sure your computer meets the minimum hardware and software requirements and that your network is configured appropriately.

Hardware Requirements

This release of Oracle VM Server supports x86_64 host hardware only. Oracle VM Server requires a 64-bit processor with at least an i686-class processor on the host computer. This includes all Intel Pentium Pro or newer, and all AMD Athlon/Duron processors and newer. At least a Pentium 4 or Athlon CPU is recommended.
For hardware virtualized (unmodified) guest operating systems (for example, Microsoft Windows), a CPU with hardware virtualization support is required. This includes some Intel Pentium D, Core, Core2 and Xeon models, and some AMD Athlon and Opteron models. This feature may also need to be enabled in the BIOS. Please refer to your processor documentation for information on whether your processor supports hardware virtualization and how to enable it in the BIOS.
A dual core CPU or multiple CPUs are recommended to run multiple guests.
The minimum memory requirement is 1 GB RAM, although it is recommended you have a computer with at least 2 GB RAM. Guest memory requirements vary for each guest operating system. You should perform your own memory sizing for guest operating systems.
It is also worth noting that if you intend to connect to SAN-based physical disks, memory consumption increases on the server for each LUN or target by around 1 MB per LUN or target. If hundreds of LUNs are to be attached to the server, you must scale memory requirements appropriately.

Software Requirements

There are no prerequisite software requirements. Oracle VM Server includes a small Linux-based management operating system. All previous operating systems and data on the disk selected for installation are lost during the installation of Oracle VM Server.
Migration from any operating system, or previous alternate virtualization environment, is not supported in this release.

 Network Requirements

Oracle VM Server requires at least one stable and static IP address that does not change over server reboots. If you use DHCP within your environment, you should configure your DHCP server to assign static DHCP addresses to the systems on which you will be installing Oracle VM Server. This ensures that your host always receives the same IP address. The behavior of the Oracle VM Server host is undefined if used in an environment where your IP address may change due to DHCP lease expiry.
If your DHCP server is configured to provide a default gateway, this could impact on the behavior of Oracle VM Server as the gateway provided over DHCP would override any statically defined gateway set on Oracle VM Server. Therefore, Oracle recommends that you ensure that your DHCP server is not configured to provide a default gateway unless you are certain that the default route is the one that you want your Oracle VM Server instances to make use of.
Many actions performed within Oracle VM Manager require that server hostnames are properly resolved. It is highly recommended that a DNS server is configured on your network and that the hostnames for each Oracle VM Server can be resolved by all of the systems within your Oracle VM environment. If this is not feasible, you may need to add host entries to /etc/hosts on each Oracle VM Server after you have finished your installation. Since it is easy for these entries to become outdated, resulting in difficulty when troubleshooting, this approach should be avoided.
Technically, it is possible to run Oracle VM Server with a single network interface per physical server. During the installation of each Oracle VM Server the management interface is configured, and during discovery by Oracle VM Manager the server management interfaces are included in the default management network. Since the management network is capable of providing all network functions in Oracle VM, including storage and virtual machine traffic, there is no functional need for additional networks. Even if you wish to separate different types of network traffic, a single interface is enough: the management network can be run on a VLAN and additional network connections can be made via VLAN interfaces configured on top of the single physical network interface.
The main reasons to opt for multiple physical network interfaces are:
  • Security. You may wish to keep internal and inter-server traffic separated from networks with a route to the internet. Or you may need to guarantee that network traffic from different virtual environments, or different types of network traffic, are physically separated.
  • Redundancy. You do not want your environment to stop working if one network interface fails. A good way to avoid this is to aggregate two interfaces in a bond interface. A bond port, as it is called in Oracle VM, can work in active-backup mode, but also increases performance when used as an aggregation of two active links with twice the bandwidth and load balancing.
  • Performance. If you have multiple physical network interfaces, link aggregation is a good way to add bandwidth for a given network function. In addition, or as an alternative, you can create multiple physical networks and use them for dedicated functions; for example a separate storage network or a network for virtual machine traffic only.
Note
Oracle VM Ethernet network functionality can be applied to standard 10/100/1000Mbit Ethernet interfaces as well as 10Gbit Ethernet interfaces.

Oracle VM Server Memory Settings

Installation allocates memory to dom0 using the following algorithm:
(512 + 0.0205 * Physical memory (MB)) round to 8
Oracle does not recommend changing this default value.


To install Oracle VM Server from a DVD-ROM or CD-ROM:
  1. Make sure that the server BIOS is set to boot from the DVD-ROM or CD-ROM device.
  2. Insert the Oracle VM Server DVD or CD, that you have burned, into your ROM drive.
  3. Boot the server with the Oracle VM Server DVD or CD.
  4. The Oracle VM Server screen is displayed. Press Enter to begin the installation. If you do not press a key for one minute, the installer automatically starts. The installer is only available in text mode.
  5. The CD Found screen is displayed. If you want to make sure the DVD or CD has been created correctly you can have the installer test it for errors. To test the DVD or CD, select OK and press Enter. The DVD or CD is tested and any errors are reported.
    Warning
    Testing the installation media requires a server reboot to continue the installation. If you do not have physical access to the server itself, it is not recommended that you perform this test.



To skip media testing and continue with the install, select Skip and press Enter.





The Language Selection screen is displayed. Select the language that should be used for the operating system (for example English).

Select OK and press Enter


  1. The Keyboard Selection screen is displayed. Select the keyboard layout type (for example, us for U.S. English) from the list of available options. The keyboard you select becomes the default keyboard for the operating system.
    Select OK and press Enter.

  1. The Oracle VM Server 3.x End User License Agreement screen is displayed. Read the License Agreement text and click Accept to accept the terms of the agreement and continue the installation.


The Partitioning Type screen is displayed. Select whether you want to:
  • Use the entire drive for the installation target
  • Replace the existing Linux system (if any)
  • Use the free space on selected drives to create a new default partition layout
Select which drive(s) you want to use for the installation.
Select OK and press Enter







The Oracle VM Management Interface screen is displayed. Select the network interface to use for management of the computer.
Choose one of these options:
Select OK to connect the interface to a regular network.
Select Add to VLAN to connect the interface to a VLAN-type network.

Press Enter
.

  1. For non-VLAN installation, proceed to the next step.
    If you selected Add to VLAN, the Oracle VM Management VLAN screen is displayed. If your Oracle VM Management network is on a VLAN, enter the applicable VLAN tag. Note that 0 is reserved and that 1 corresponds with "untagged".
    Select OK and press Enter.
  2.  The Network Interface Configuration screen is displayed. If your computer uses a static IP address, enter the IP address and prefix (netmask) for your computer.
    If your computer uses DHCP to assign its IP address, select Dynamic IP configuration (DHCP).
    Select OK and press Enter.
  3. The Miscellaneous Network Settings screen is displayed. Enter the Gateway, Primary DNS and optional Secondary DNS in the respective fields.
    Select OK and press Enter.



 The Hostname Configuration screen is displayed. If your machine has its own hostname, select manually and enter the hostname or IP address. You should use a fully qualified hostname, for example, myserver.example.com.



The Time Zone Selection screen is displayed. If your operating system uses Coordinated Universal Time (UTC), select System clock uses UTC.
Select your time zone by selecting the city closest to your computer's physical location.
Select OK and press Enter




  1. The Oracle VM Agent password screen is displayed. Enter a password to be used for the Oracle VM Agent in the Password field. This password is used by Oracle VM Manager to take ownership of the Oracle VM Server. This is the password you use when discovering Oracle VM Servers in Oracle VM Manager.
    Re-enter the password in the Password (confirm) field.
    The password characters are not echoed to the screen.
    Select OK and press Enter. If the two passwords do not match, the installer prompts you to enter them again.

  1. The Root Password screen is displayed. Enter a password for the root user in the Password field. The root password must be at least six characters long.
    Re-enter the password in the Password (confirm) field.
    The password characters are not echoed to the screen.
    Select OK and press Enter. If the two passwords do not match, the installer prompts you to enter them again.




  1. The Writing storage configuration to disk screen is displayed to confirm that you want to write the partitioning information to disk, proceeding past this step will erase any data contained on the partition that you opted for in the previous step.
    Select Write changes to disk and press Enter.
  2. The Installation to begin screen is displayed. Select OK and press Enter. The installer installs and configures Oracle VM Server. You can follow the progress of the package installation on-screen.
  3. When all files are installed and configuration is complete, the Complete screen is displayed. Remove the Oracle VM DVD or CD.
    Select Reboot and press Enter. The computer reboots.
The Oracle VM Server installation is complete. The Oracle VM Agent is started automatically and restarts each time the computer is rebooted.