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Windows 8 : Working with Disks, Partitions, and Volumes, Using Disk Mirroring (part 2) - Creating Spanned and Striped Volumes, Shrinking or Extending Volumes
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9/11/2013 8:07:08 PM
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Creating Spanned and Striped Volumes
With spanning and striping, you create a single volume that extends
across multiple disks. When working with spanning and striping, keep
the following in mind:
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A spanned volume uses free space on multiple disks of the same type.
If you have unallocated space on two or more disks of the same type,
you can combine this space to create a spanned volume. A spanned volume
has no fault tolerance and has average read/write performance. Files
are written to the entire spanned volume randomly. If any one of the
disks fails, the entire volume fails as well, and all data is lost. -
A striped volume uses free space on multiple disks and stripes the
data as it is written. Striping gives you faster read/write access to
data because data is read from and written to multiple disks. For
example, with a three-disk striped volume, data from a file will be
written to Disk 1, then to Disk 2, and then to Disk 3 in 64-KB blocks.
Like a spanned volume, a striped volume has no fault tolerance, so if
any one of the disks fails, the entire volume fails as well, and all
data is lost. This approach also is referred to as RAID 0. -
A striped with parity volume uses three or more volumes, each on a
separate drive, to create a striped set with parity error checking. In
the case of failure, data can be recovered. This approach, also
referred to as RAID 5, gives fault tolerance with less overhead than mirroring and better read performance than disk mirroring.
Note
If you have only one disk available, you will not be able to create
a spanned or striped volume. Also note that simple and spanned volumes
can be extended to increase their volume size. RAID 0 and RAID 5
volumes, however, cannot be extended. When you create a RAID 0 or RAID
5 volume, you should be very certain that the volume size is what you
want to use. Otherwise, you might have to delete and then re-create the
striped volume. Additionally, the boot and system volumes shouldn’t be
part of a RAID 0 or RAID 5 set. Don’t use RAID 0 or RAID 5 with these
volumes.
Note
MORE INFO To allow for fault
tolerance, RAID 5 writes parity checksums with the blocks of data. If
any of the drives in the striped set fails, you can use the parity
information to recover the data. If two disks fail, however, the parity
information isn’t sufficient to recover the data, and you’ll need to
rebuild the striped set from backup.
In Disk Management, you create spanned or striped volumes on disks by completing the following steps:
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In Disk Management’s Graphical view, press and hold or right-click
an unallocated area, and then tap or click New Spanned Volume, New
Striped Volume, or New RAID-5 Volume, as appropriate. Read the Welcome
page, and then tap or click Next. Keep in mind that although Windows 8
supports spanning and striping on basic disks, some basic disks cannot
be spanned or striped. -
On the Select Disks page, select the disks that will be part of the
volume and specify the size of the volume segments on those disks. The
disks must be the same disk type, either basic or dynamic. Tap or click
Next.
Available disks are shown in the Available list. Select a disk in
this list, and then tap or click Add to add the disk to the Selected
list. If you make a mistake, you can remove a disk from the Selected
list by selecting the disk and then tapping or clicking Remove.
Specify the space that you want to use on each disk by selecting
each disk in the Selected list and then using Select The Amount Of
Space In MB to specify the amount of space to use. Keep in mind that
the Maximum box shows you the largest area of free space available on
the selected disk, and the Total Volume Size box shows the total disk
space currently allocated to the volume.
Tip
There’s a quick way to use the same amount of space on all selected
disks. To do this, highlight each disk by pressing Shift and then
tapping or clicking the first disk and the last disk in the Selected
list. Now, when you set the amount of space to use, you’ll set the
amount for all selected disks.
-
Follow steps 3–5 in the previous section, Creating Partitions, Logical Drives, and Simple Volumes.
Shrinking or Extending Volumes
Windows 8 doesn’t use Ntldr and Boot.ini to load the operating
system. Instead, Windows 8 has a preboot environment in which Windows
Boot Manager is used to control startup and load the boot application
you’ve selected. The Windows Boot Manager also frees the Windows
operating system from its reliance on MS-DOS, enabling you to use
drives in ways you couldn’t before. Windows 8 enables you to extend and
shrink both basic and dynamic disks. You can use Disk Management or
DiskPart to extend and shrink volumes. You cannot shrink or extend striped volumes.
In extending a volume, you convert areas of unallocated space and add them to the existing volume. For spanned
volumes on dynamic disks, the space can come from any available dynamic
disk, not only those on which the volume was originally created. This
enables you to combine areas of free space on multiple dynamic disks
and use those areas to increase the size of an existing volume.
Caution
Before you try to extend a volume, you should know about several
limitations. First, simple and spanned volumes can be extended only if
they are formatted and the file system is NTFS. You can’t extend
striped volumes. You can’t extend volumes that aren’t formatted or that
are formatted with FAT, FAT32, or exFAT. Additionally, you can’t extend
a system or boot volume, regardless of its configuration.
You can shrink a basic volume, simple volume, or a spanned volume by completing the following steps:
-
In Disk Management, press and hold or
right-click the volume that you want to shrink, and then tap or click
Shrink Volume. This option is available only if the volume meets the
previously discussed criteria. -
In the Shrink dialog box, shown in Figure 4, enter the amount of space by which to shrink the disk. The Shrink dialog box provides the following information:
-
Total Size Before Shrink In MB Lists the total capacity of the volume in megabytes. This is the formatted size of the volume. -
Size Of Available Shrink Space In MB
Lists the maximum amount by which you can shrink the volume. This
doesn’t represent the total amount of free space on the volume; rather,
it represents the amount of space that can be removed, not including
any data reserved for the master file table, volume snapshots, page
files, and temporary files. -
Enter The Amount of Space To Shrink In MB
Lists the total amount of space that will be removed from the volume.
The initial value defaults to the maximum amount of space that can be
removed from the volume. For optimal drive performance, you should
ensure that the volume has at least 10 percent of free space after the
shrink operation. -
Total Size After Shrink In MB
Lists what the total capacity of the volume in megabytes will be after
you shrink the volume. This is the new formatted size of the volume.
-
Tap or click Shrink.
You can extend a basic volume, simple volume, or a spanned volume by completing the following steps:
-
In Disk Management, press and hold or right-click the volume that
you want to extend, and then tap or click Extend Volume. This option is
available only if the volume meets the previously discussed criteria
and free space is available on one or more of the system’s disks. -
In the Extend Volume Wizard, read the introductory message, and then tap or click Next. -
On the Select Disks page, select the disk or disks from which you
want to allocate free space. Any disks currently being used by the
volume will automatically be selected. By default, all remaining free
space on those disks will be selected for use. -
You can specify the additional space that you want to use on other disks by performing the following tasks:
-
In the Available list, tap or click the disk, and then tap or click Add to add the disk to the Selected list. -
Select each disk in the Selected list, and then use Select The
Amount Of Space In MB to specify the amount of unallocated space to use
on the selected disk.
-
Tap or click Next, confirm your options, and then tap or click Finish.
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