Welcome to the ITFreeTraining video on MBR and GPT Partition tables. In this video I
will go through how to configure MBR and GPT partition tables on Windows 8 and Windows
Server 2012 both at the command line and also using the graphics interface. So without further
ado, I will change to my Windows 8 computer.
To access disk management, I will first open Windows Explorer from the quick launch bar.
Once open, I will right click on computer and select the option manage. This will open
Computer Management. Disk Management can be found in computer management under Storage.
In this computer I have added a brand new hard disk that has not been formatted as yet.
If I cursor over it notice that there is a down arrow indicating that the hard disk is
currently offline. Notice under this, it is also indicated that the hard disk has not
as yet been initialized. Initializing the hard disk adds a signature to the hard disk.
This signature allows Windows to identify the hard disk even if the hard disk is moved
to a different controller or moved to a different computer.
Before I can use the hard disk I need to initialize it. To do this, right click the disk and select
initialize disk. Initialize disk will create a partition table on the hard disk which will
define how data on the hard disk can be stored.
The next step is to decide which partition table you want to use. You can see that you
have the options for MBR Master Boot Record and GPT GUID Partition Table. In this case,
I will leave it on the default option MBR and press o.k. In the real world, if your
hard disk is smaller than 2 Terabytes, then MBR should meet all your needs.
You can see that Disk 1 status has now changed to online. If you decide you want to use GPT
later on, notice that when I right click the disk, I have the option convert to GPT disk.
The only reason this option is available is because there is no volume defined on the
hard disk.
To demonstrate this better, I will create a volume on the hard disk by right clicking
the hard disk and selecting the option new simple volume. It does not matter which options
I choose in the new simple volume wizard so I will choose all the default options for
the wizard and next my way to the end.
Notice that once the volume is created, if I right click the hard disk, the option Convert
to GPT disk is now grayed out. If you want to convert the partition table to GPT, you
need to first delete all the partitions on the hard disk. Notice that when I delete the
volume the option to convert it to GPT disk is now available. If I select this option
nothing appears to happen, however if I right click the disk again, notice that the option
has changed to convert to MBR disk.
This gives you an indication of which partition table is in use. If I select the option properties
then select the tab volume, notice that under partition style the partition type is shown
as GUID Partition table.
I will now change to my Windows Server 2012 and have a look at some of the differences
in the interface compared with Windows 8.
To access disk management on Windows Server 2012, I will first open server manager and
from server manager select the tools menu and from that select the option Computer Management.
Notice that I have a hard disk that has not been initialized. When I move the mouse over
this hard disk notice that it states that “The disk is offline because of policy set
by an administrator.” In order to use this hard disk, the administrator needs to right
click and select online.
Having to manually online new hard disks is a policy configured by default in Windows
Server 2012 to prevent a hard disk from a San’s accidently being added and used by
the server. Since a San could share storage between many different servers, potentially
2 servers could attempt to write to the same drive at the same time. For this reason, Windows
Server 2012 requires an administrator to physically go into disk management and select the online
option for any new storage added to the server. This helps prevent storage being used on multiple
servers by accident.
To change this policy, this needs to be done from a command line utility called DiskPart.
To access it, I will close these Windows and press the Windows key followed by the X key
to open the quick launch menu and select command prompt.
Once the command prompt opens, I will enter in DiskPart. DiskPart is a utility included
in Windows and allows you to perform the same functions as you can in Disk Management
plus some additional functions.
To see the San policy which is currently configured I will enter in San. You can see that policy
is currently configured to “Offline Shared”. Any new disks that are added to the system
will automatically be placed in an offline state.
To change this, I need to enter in the command SAN Policy=OnlineAll. This will change the
default setting so that any new disks added to the system will automatically be borrow
online. If you do enable this setting, be careful if you introduce any foreign disks
into the system. A new disk could cause issues with the other drives in the system. One site
I worked on changed a server to boot from the SAN. It previously booted off local hard
disks which were still in the system. During a power outage all the servers and the SAN
were switched off. When they started up the server started up faster than the SAN. Since
the SAN was not available, you guessed it, the server failed the SAN boot and then booted
of the local hard disks containing the operating system from 2 months ago. Lucky the problem
was picked up quickly and the server reconfigured to boot only off the SAN and not the local
drives, but you get the idea of how much potential damage any changes in the disks in a server
could have.
Now that it is complete, I will press Windows X again and this time select the option for
run. This time I will run Disk Management by running “DiskMGMT.MSC”. Running Disk
Management like this allows Disk Management to utilize more of the screen than if it is
accessed through Computer Management.
Notice that the drive is still offline. Since I have just changed the policy, the policy
change will only effect new drives that are added to the system, not drives that are already
present in the system.
If I right click the drive, I can select the online option and then I can right click the
drive and select initialize the drive just like I could in Windows 8. Just like Windows
8 you have the choice of MBR or GPT. I will leave in on the default of MBR and press o.k.
Notice also once the disk has been initialized, if I right click the drive I can convert it
to GPT so besides having the extra San policy for Windows Server 2012, the interface looks
the same as it did in Windows 8.
All the functions that I just preformed can also be run from the command line DiskPart
utility. If go back to the command prompt which is still running DiskPart, I will now
go through the process I just went through with Disk Management with DiskPart.
To find out which disks are installed on this system, I will run the command list disk.
This will show any disks that are currently installed on this server. Before I can perform
any actions on any of the disks I need to select one of them. This is done with the
select disk command followed by the number of the disk. In this case I will select disk
1.
Once the disk is selected a number of different commands can be run. This includes creating
partitions. In this case, I will run the command convert GPT. This will change the partition
table to the GPT partition table, just like what I did with the Disk Management interface.
Also just like the Disk Management tool, I can also change the partition table back to
MBR using the command convert MBR.
You will notice that DiskPart did not give any warning message or confirmation messages
before it executed the command. For this reason you should always be careful with DiskPart
as it is easy to erase the wrong disk by mistake. If you are not sure which disk you are currently
working on you should run the command list disk again and you will notice that there
is an asterisk next to the disk that is currently selected.
The last command that I will look at is clean. The clean command will remove all configuration
data from the hard disk and thus effectively erase the disk.
To demonstrate this better, I will once again run Disk Management using the run command
like I did before. Notice this time Disk Management has detected the disk and asked how you would
like it partitioned. If you had recently installed a brand new disk that had never been used
before you would get this screen. So effectively the clean command has removed everything from
the hard disk, including the signature that Windows adds to identify the hard disk. As
far as Windows is concerned, this is a brand new disk that has never been used before.
Well that covers it for MBR and GPT. I hope you have found this video from ITFreeTraining
useful. Remember this is only one of the free videos available from ITFreeTraining. Thanks
for watching and hope to see you next time.