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Windows 8 : Working with Disks, Partitions, and Volumes, Using Disk Mirroring (part 4)
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9/11/2013 8:09:40 PM
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Deleting Partitions, Volumes, and Logical Drives
To change the configuration of an existing drive that’s fully
allocated, you might need to delete existing partitions, logical
drives, or volumes. Because this deletion is irreversible, you should
always back up and verify any important files and folders before
deleting a partition, a logical drive, or a volume. If a computer has
spanned or striped volumes, be careful when deleting volumes. Deleting
any volume in a set erases the entire volume set, meaning the entire
volume and all its data are lost.
Caution
Deleting a partition, a logical drive, or a volume is a drastic step
that cannot be reversed. It removes the associated file system, and all
data in the file system is lost.
Note
To protect the integrity of the system, you can’t delete the system
or boot partition. However, Windows 8 lets you delete the active
partition or volume if it is not designated as boot or system. Always
check to be sure that the partition or volume you are deleting doesn’t
contain important data or files.
You can delete a primary partition, a volume, or a logical drive by completing the following steps:
-
In Disk Management, press and hold or right-click the partition,
volume, or drive you want to delete, and then tap or click Explore.
Using File Explorer, move all the data to another volume or verify an
existing backup to ensure that the data was properly saved. -
In Disk Management, press and hold or right-click the partition,
volume, or drive again, and then tap or click Delete Partition, Delete
Volume, or Delete Logical Drive, as appropriate. -
Tap or click Yes to confirm that you want to delete the selected item.
Deleting an extended partition is a slightly different operation
from deleting a primary partition or a logical drive. To delete an
extended partition, you must first delete all the logical drives on the
partition by following the steps in the preceding procedure. You can
then select the extended partition area itself and delete it.
Converting a Volume to NTFS
Windows 8 provides a command-line utility for converting FAT or
FAT32 volumes to NTFS. This utility, named Convert (Convert.exe), is
located in the %SystemRoot%\System32 folder. When you convert a volume
using this tool, the file and directory structure is preserved and no
data is lost.
Caution
Windows 8 doesn’t provide a utility for converting NTFS to FAT or
FAT32. The only way to go from NTFS to FAT or FAT32 is to delete the
partition by following the steps outlined in the previous section and
then re-create the partition as a FAT or FAT32 volume. Note also that
Convert doesn’t convert exFAT volumes to NTFS.
If you want to convert a drive, use the following syntax at an elevated command prompt:
convert volume /FS:NTFS
where volume is the drive letter followed by a colon (:), a drive path, or a volume name. For example, if you want to convert drive D to NTFS, you would use the following command:
convert D: /FS:NTFS
The complete syntax for the Convert command is
Convert volume /FS:NTFS [/V] [/X] [/CvtArea:filename] [/NoSecurity]
These options and switches are used as follows:
-
volume Sets the
volume to work with and must include the full drive designator (the
drive letter followed by a colon). You also can specify a mount point
or volume name. -
/FS:NTFS Converts the designated volume to NTFS. This is the only file system option. -
/V Sets verbose mode, which provides more detail in the output. -
/X Forces the volume to dismount before the conversion (if necessary). -
/CvtArea : filename
Specifies a contiguous file in the root directory to
be the placeholder for the NTFS system files stored on the MFT. If you
omit a file name, Convert uses the default configuration and reserves
12.5 percent of the partition or volume size. This helps to prevent
fragmentation of the MFT. -
/NoSecurity Sets
the NTFS security settings on all files and folders so that the
Everyone group can access them. This effectively makes the entire file
system accessible to anyone who can access the system locally or
remotely.
Before starting the conversion, the Convert command checks whether
the drive has enough free space to perform the conversion. Generally,
Convert needs a block of free space that’s equal to roughly 25 percent
of the total space used on the drive. For example, if the drive stores
100 GB of data, Convert needs about 25 GB of free space. If there isn’t
enough free space, Convert cancels the operation and tells you that you
need to free up some space. On the other hand, if there is enough free
space, Convert initiates the conversion. Be patient. The conversion
process takes several minutes (longer for large drives). Don’t access
files or applications on the drive while the conversion is in progress.
Note
Before using the Convert command, double-check whether the partition
is being used as the active boot partition or a system partition
containing the operating system. With MBR disks, you can convert the
active boot partition to NTFS. Doing so requires that the system gain
exclusive access to this partition, which can be obtained only during
startup. Thus, if you try to convert the active boot partition to NTFS,
Windows 8 displays a prompt asking if you want to schedule the drive to
be converted the next time the system starts. If you tap or click Yes,
you can restart the system to begin the conversion process. Often,
several restarts of a system are required to completely convert the
active boot partition. Don’t panic. Let the system proceed with the
conversion.
Note
You can improve
performance on the volume using the /CvtArea option so that space for
the MFT is reserved. This option helps prevent fragmentation of the
MFT. How? Over time, the MFT might grow larger than the space allocated
to it. The operating system must then expand the MFT into other areas
of the disk. Although the Windows 8 Disk Defragmenter utility can
defragment the MFT, it cannot move the first section of the MFT, and it
is very unlikely that there will be space after the MFT because this
will be filled by file data.
To help prevent fragmentation in some cases, you might want to
reserve more space than the default (12.5 percent of the partition or
volume size). For example, you might want to increase the size of the
MFT if the volume will have many small or average-size files rather
than a few large files. To specify the amount of space to reserve, you
can use FSUtil to create a placeholder file equal in size to that of
the MFT you want to create. You can then convert the volume to NTFS and
specify the name of the placeholder file to use with the /CvtArea
option.
Here, I use FSUtil to create a 1.5-GB (1,500,000,000 bytes) placeholder file named Temp.txt:
fsutil file createnew c:\temp.txt 1500000000
To use this placeholder file for the MFT when converting drive C to NTFS, you would type the following command:
convert c: /fs:ntfs /cvtarea:temp.txt
Notice that the placeholder file is created on the partition or
volume that is being converted. During the conversion process, the file
is overwritten with NTFS metadata and any unused space in the file is
reserved for future use by the MFT.
Recovering a Failed Simple, Spanned, or Striped Volume
Basic partitions and simple volumes are fairly easy to troubleshoot
and recover because only one disk is involved. Spanned or striped
volumes, on the other hand, might have multiple disks. If disks don’t
have striping with parity, the failure of any one disk makes the entire
volume unusable. The drive status might show that the drive is Missing,
Failed, Online (Errors), Offline, or Unreadable.
You might see the Missing (and sometimes Offline) status if drives
have been disconnected or turned off. If the drives are part of an
external storage device, check the storage device to ensure that it is
connected properly and has power. Reconnecting the storage device or
turning on the power should make the drives accessible. You then must
start Disk Management and rescan the missing drive. Press and hold or
right-click the missing drive, and then tap or click Rescan Disks. When
Disk Management finishes, press and hold or right-click the drive, and
then tap or click Reactivate.
You might see the Failed, Online (Errors), and Unreadable status
notifications if a drive has I/O problems. As before, try rescanning
the drive and then try to reactivate it. If the drive doesn’t come back
to the Healthy state, you might need to replace it.
Tip
Sometimes you might need to reboot the computer to get a disk back
online. If this still doesn’t resolve the problem, check for problems
with the drive, its controller, and the cables. Also, make sure that
the drive has power and is connected properly.
Regenerating a Striped Set with Parity
With RAID 5, you can recover the striped set with parity if a single
drive fails. You’ll know that a striped set with parity drive has
failed because the set’s status changes to Failed Redundancy and the
individual volume’s status changes to Missing, Offline, or Online
(Errors).
You can repair RAID-5 disks, but you must rebuild the set using
disks with the same partition style—either MBR or GPT. You need to get
all drives in the RAID-5 set online. The set’s status should read
Failed Redundancy. The corrective action you take depends on the failed
volume’s status:
-
If the status is Missing or Offline, make sure that the drive has
power and is connected properly. Then open Disk Management, press and
hold or right-click the failed volume, and select Reactivate Volume.
The drive’s status should change to Regenerating and then to Healthy.
If the drive’s status doesn’t return to Healthy, press and hold or
right-click the volume and select Regenerate Parity. -
If the status is Online (Errors), press and hold or right-click the
failed volume and select Reactivate Volume. The drive’s status should
change to Regenerating and then to Healthy. If the drive’s status
doesn’t return to Healthy, press and hold or right-click the volume and
select Regenerate Parity. -
If one of the drives shows as Unreadable, you might need to rescan
the drives on the system by choosing Rescan Disks from the Action menu
of Disk Management. If the drive status doesn’t change, you might need
to reboot the computer. -
If one of the drives still won’t come back online, you will need to
repair the failed region of the RAID-5 set. Press and hold or
right-click the failed volume, and then select Remove Volume. You now
need to select an unallocated space on a separate dynamic disk for the
RAID-5 set. This space must be at least as large as the region to
repair, and it can’t be on a drive that the RAID-5 set is already
using. If you don’t have enough space, the Repair Volume command is
unavailable, and you need to free up space by deleting other volumes or
by replacing the failed drive.
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