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.
