MCTS 70-680: Dynamic Disks and Raid

Here we go again for anther free video for Windows 7 part of the free training course
for the 70-680 exam. In this video I will look at dynamic disks and Raid. One terminology
I want to make clear before getting started is the difference between a partition and
a volume. Understanding the difference between the two becomes important when dealing with
data that is spread over multiple disks. A partition in simple terms is dividing a
hard disk into multiple storage areas. This may be done for a number of different reasons.
In some cases you may want to separate your operating system from your data. Multiple
partitions can also be used to keep your virtual memory or paging files separate from the operating
system. In systems such as linux this is quite common.
Storing the virtual paging file on a separate partition on the same hard disk as the operating
system has little to no speed improvements. To get speed improvements you are best to
put the paging file on a separate hard disk from the operating system.
If you are running multiple operating systems you can use partitions to keep these operating
systems separate. With virtualization becoming more popular this is not happening as much.
If you wanted to run anther operating system it is easier in most cases to run the operating
system in a virtual machine rather than creating multiple partitions on your hard disk.
A volume is different from a partition as it is defined as a single accessible logical
storage area. It uses partitions at its building blocks to build a volume. This means that
a volume can use one partition or use multiple partitions on multiple disks. The key point
to remember is that a volume is defined as one storage area. To put it another way, a
volume will appear in Windows explorer as one drive regards of how many disks and partitions
it uses. When you use disk management in Windows 7
to create a volume, disk management will automatically create any required partitions for that volume.
You may not have even known that partitions had existed before now as disk management
does a great job of doing all the hard work for you.
When you first install a hard disk in Windows 7 it will be installed as a basic disk.
Basic disks are supported in all versions of Windows so offer great compatibility. With
a basic disc you can shrink or extend the volume. In other words you can make it bigger
or smaller. You can even shrink or extent the system or boot partition.
The next type of disk type that Windows 7 supports is dynamic disks. Dynamic disks support
more features than simple disks however do require Windows 7 professional or above. Since
dynamic disks are a Microsoft solution alterative operating systems will not be able to read
dynamic drives. Besides having more features than basic disks,
the big difference with dynamic disks is that it uses logical disk management. Logical disk
management also referred to as LDM, reverses a small part of the hard disk to write additional
configuration information about the drive. This information is replicated to all the
other dynamic hard disks in the computer. The information in the LDM contains information
about hard disk drive managment. This means that if you move the hard disk from one computer
to anther computer the hard disk drive letter will be remembered. Also if you move the hard
disk from one controller to anther the drive letter will also not change. If you are currently
using basic disks you can convert your basic disk to a dynamic disk. This is a one way
process so you will not be able to go back to basic disks without losing all the data
on the drive. Dynamic disks support multiple hard disks
combined together to form a set. The first way this can be done is using a spanned set.
A spanned set combines all the free space from multiple drives into one logical hard
disk. The free space on each drive can be different sizes and is a good way of making
use of free space without having to create multiple drives each with their own drive
letter. Creating a spanned set allows you to use the
free space that may have otherwise being wasted but it does not give any performance improvements.
Also if one drive fails in the set, all the data in the spanned set will be lost.
The next type of disk set that Windows 7 supports is Raid. Raid or Redundant array of independent
disks is when multiple hard disks are combined together for performance or redundancy reasons.
There are a lot of different ways RAID can be configured. Windows 7 supports two of these.
These are RAID 0 and RAID 1. One thing that I want to point out is that Windows RAID support
is software. Now days a lot of hardware supports RAID. If you are thinking about using RAID,
considering looking to see if your motherboard supports hardware RAID. Hardware RAID generally
performs faster than software RAID. Raid 0 is often referred to as a striped set.
RAID 0 is when the data from the hard disks in the set are evenly spread out over all
the drives in the set. As shown here, files on the hard disks are divided up into parts
and stored on the two drives. You need at least two hard drives to have a Raid 0 volume
or stripped set but you can have more. As shown here, if you had four hard disks in
the set, the data is once again spread out over all the four drives.
The advantage with multiple hard disks is that read and write performs is increased.
A shown here, when you read from the Raid 0 drive, all hard disks work at the same time
to read the file. Also if the file is updated, once again, all hard disk write at the same
time to update the file. There are two disadvantages with raid 0 drives.
The first is that if one of the hard disks is to fail then you lose all the data in the
set. The second disadvantage with Raid 0 drives is that you cannot boot Windows 7 from a Raid
0 hard disk. If you want to do this you will need to use a hardware based RAID solution.
This is because Raid 0 in Windows 7 is software based, the operating system must boot first
so that Windows can access the drive. For this reason, Raid 0 drives are usually used
for data drives or even for the paging file. If you decide to use Raid 0 remember that
all your hard disks in the set must be the same size. If you use hard disks of different
sizes the raid set size will be a multiple of the smallest hard disk in the set. The
additional space on each hard disk will not be used in the raid 0 set and will remain
unallocated space. The next type of Raid that Windows 7 supports
is Raid 1 also known as a mirror set. A mirror set requires 2 hard disks to operate. The
advantage of Raid 1 is that the drive can still function if one of the hard disks were
to fail. Since both hard disks contain the same information there is no problem booting
from a Raid 1 hard disk so you can use Raid 1 for the operating system and data drives.
The disadvantage with Raid 1 is that there is no performance advantage. You get redundancy
by having your data in two places but in the process your data costs effectively double.
Now that you understand the basis of basic and dynamic disk, let’s have a look at how
to use them in Windows 7. First of all I will open disk management tool
from the start menu by running diskmgmt.msc from the start menu. In this computer
I have put in anther dynamic hard disk from the anther computer. Notice that this disk
has come but as foreign. If the disk were a basic disk it would not come up as a foreign
disk it would appear as anther disk. The extra configuration data on the disk provided by
logical disk management allows Windows to recognize this hard disk is from anther system.
To make this hard disk accessible on this system right click and select the option import
foreign disk. Once selected Windows will tell me which disks are been imported. Since this
is a dynamic disk it could be one hard disk out of a set of hard disks. If any hard disks
were missing Windows would informing me since the configuration information for a set of
disks is stored on every hard disk in the set.
Once I press o.k. I will be given a dialog telling me which volumes are on this hard
disk are being imported. Once I press o.k. the hard disk will be imported.
Notice that when the hard disk is imported it is given the drive letter T. This is the
drive letter I assigned this hard disk on the other system. Thanks to the extra information
stored on dynamic disks, Windows is able to determine the drive letter of the hard disk.
I don’t need the data on this hard drive so I will go ahead and delete the volume on
the hard disk. Disk 0 on this system is a basic disk, notice that when I right click
disk 0 I have the option to convert this disk to a dynamic disk.
In this case I will leave the disk as a basic disk to prove a point. When I right click
on the system reserved volume I get the option to add a mirror. This is basically making
the volume a raid 1 drive. When I select add mirror, Windows will give me a list of all
the hard disks that have enough space to store the mirror drive on.
When I select a drive and move on I will get a message telling me that the hard disks will
need to be converted to a dynamic disk before I can continue. Since Windows will prompt
you anyway, you don’t need to worry about converting your hard disks to dynamic before
setting up a mirror set. Once I press yes I will get another dialog
telling me the boot configuration of the drive could not be updated. What this is basically
saying is that Windows will be able to boot off disc 0, however if disk 0 were to fail the
system will not boot until you modify the startup configuration. This can be done using
bcdedit using a Windows PE boot disk. This is limitation of Windows to boot of mirrored
drives. This is why I would personally use a hardware solution to mirror the system drive.
If I select one of the volumes that is on a dynamic disk notice that I have the option
to shrink and extend the volume just like I had with basic disks. If I go down to one
of the free hard disk and right click it, I get the option to create a new striped volume.
A stripped volume is Raid 0. Once I select this option the wizard will start and I am
asked which hard disks I want to use in the striped volume. In this case I will select
4 hard disks to use in the stripped set. Just like when I created a simple volume I will
be asked for a drive letter, volume name and formatting options.
Some of the hard disks are basic so Windows will ask me to upgrade them to dynamic before
continuing. The new striped volume has been created and added as Raid 0 in the disk manager.
The other hard disks in the system were 50 gigabytes and this hard disk is 128 gigabytes
so you can see at the end of this hard disk is 77 gigabytes of unused space.
If I scroll up to the top there are 3 drives with space at the end that is not being used.
To combine all this space into one drive all I need to do is right click on some of the
unused space and select new spanned volume. This will start the spanned volume wizard.
This wizard works much the same as the other wizards, select the hard disks that you want
to use, configure the drive letter, volume and formatting options and complete the wizard.
The drive is now created. Windows 7 color codes each drive to make it easier to see.
The legend is located down at the bottom of the screen if you are not sure which is which.
Like with simple volumes it is a matter of right clicking the volume and selecting delete
volume if you don’t want the volume any more. If I right click the mirror drive that
I created earlier notice I have another option break mirrored volume. If one of the hard
disks in the mirror was to fail you could select this option to break the mirror. If
both hard disks are present and you no long need the mirror drive select the option remove
mirror. If I right click on some free hard disk space
again notice the option New Raid 5 volume. This option is grayed out. I have not covered
Raid 5 in this video because Windows 7 does not support it. To use Raid 5 you need to
be using Windows Server so don’t worry about trying to figure out how to enable it in Windows
7. This concludes the more advantaged features
of hard disks in Windows 7. In the next video I will look at the disk defragmentation tool.
As always, for additional free videos check out are YouTube channel or web page. Thanks
for watching.