Managing Windows Server 2012 Storage and File Systems : Storage Management (part 10) - Managing MBR disk partitions on basic disks - Extending partitions, Shrinking partitions

You can extend volumes on both basic and dynamic disks using either Disk Management or DiskPart. This is handy if you create a partition that’s too small and you want to extend it so that you have more space for programs and data. 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. Thus, you can combine areas of free space on multiple dynamic disks and use those areas to increase the size of an existing volume.

Before you try to extend a volume, be aware of several limitations. First, you can extend simple and spanned volumes only if they are formatted and the file system is NTFS (and in some instances, ReFS). You can’t extend striped volumes. You can’t extend volumes that aren’t formatted or that are formatted with FAT, FAT32, or exFAT. You can extend NTFS (and in some instances, ReFS) volumes on both basic and dynamic disks using either Disk Management or DiskPart.

Using Disk Management, you can extend a simple or spanned volume by following these steps:

Figure 24. Specify the amount of space to add to the volume.

By using DiskPart, you can extend partitions using the command line. To extend a partition, invoke DiskPart by typing diskpart at the command prompt. List the disks on the computer by typing list disk. After you check the free space of each disk, select the disk by typing select disk N , where N is the disk you want to work with. Next, list the partitions on the selected disk by typing list partition. Select the last partition in the list by typing select partition N , where N is the disk you want to work with.

Now that you’ve selected a partition, you can extend it. To extend the partition to the end of the disk, type extend. To extend the partition by a set amount, type extend size= N , where N is the amount of space to add in megabytes. For example, if you want to add 90 GBs to the partition, type extend size=90000.

Example 2 shows an actual DiskPart session in which a disk is extended. You can use this as an example to help you understand the process of extending disks. Here, disk 2 has 119 GBs of free space, and its primary partition is extended so that it fills the disk.

C:\> diskpart

     Microsoft DiskPart version 6.2.9200
     Copyright (C) 1999-2012 Microsoft Corporation.
     On computer: CORPSVR02

     DISKPART> list disk

       Disk ###  Status   Size    Free   Dyn    Gpt
       --------  --------  -----  -----   ---   ---
       Disk 0    Online   1560 GB 504 GB     *     *
       Disk 1    Online   1290 GB   0 B
       Disk 2    Online   370 GB  119 GB

     DISKPART> select disk 2

     Disk 2 is now the selected disk.

     DISKPART> list partition

       Partition ###   Type      Size     Offset
       -------------   --------- -------  -------
       Partition 1     Primary   370 GB    32 KB

     DISKPART> select partition 1

     Partition 1 is now the selected partition.

     DISKPART> extend

     DiskPart successfully extended the partition.

     DISKPART> exit

     Leaving DiskPart...

     C:\>

To extend a partition on a dynamic disk to free space on another disk, you use the following syntax:

extend size=X disk=Y

Here, size=X sets the amount of space to use in megabytes and disk=Y sets the number of the disk from which to allocate the space. Following this, you could allocate 50 GBs of free space from disk 0 to the selected disk in the previous example (disk 2) using the following command:

extend size=50000 disk=0

You can shrink volumes on both basic and dynamic disks using either Disk Management or DiskPart. This is handy if you create a partition that’s too large and you want to shrink it so that you have more space for other partitions. In shrinking a volume, you convert areas of allocated but unused space to free space by removing them from an existing volume.

As with extending volumes, several limitations apply to shrinking volumes. First, you can shrink simple and spanned volumes only if they are formatted and the file system is NTFS. You can’t shrink striped volumes. You can’t shrink volumes that are formatted with FAT, FAT32, exFAT, or ReFS. However, you can shrink volumes that have not been formatted. If a volume is heavily fragmented, you might have to defragment the volume to free up additional space before shrinking.

Using Disk Management, you can shrink a simple or spanned volume by following these steps:

By using DiskPart, you can shrink partitions using the command line. To shrink an NTFS-formatted partition, invoke DiskPart by typing diskpart at the command prompt. List the disks on the computer by typing list disk. After you check the free space of each disk, select the disk by typing select disk N , where N is the disk you want to work with. Next, list the partitions on the selected disk by typing list partition. Select the last partition in the list by typing select partition N , where N is the disk you want to work with.

Now that you’ve selected a partition, you can shrink it. To determine the maximum amount of space by which you can shrink the disk, type shrink querymax. To shrink the partition by the maximum amount, type shrink. To shrink the partition by a set amount, type shrink desired= N , where N is the amount of space to remove in megabytes. For example, if you want to remove 225 GBs from the partition, type shrink desired=225000.

Example 3 shows an actual DiskPart session in which you shrink a disk. You can use this as an example to help you understand the process of shrinking disks. Here you determine that there are 40 GBs of space available for shrinking on the selected partition and then shrink the partition by 32 GBs.

C:\> diskpart

   Microsoft DiskPart version 6.2.9200
   Copyright (C) 1999-2012 Microsoft Corporation.
     On computer: CORPSVR02

     DISKPART> list disk

       Disk ###  Status   Size    Free   Dyn    Gpt
       --------  --------  -----  -----   ---   ---
       Disk 0    Online   1560 GB 504 GB    *     *
       Disk 1    Online   1290 GB   0 B
       Disk 2    Online   489 GB    0 B

     DISKPART> select disk 2

     Disk 2 is now the selected disk.

     DISKPART> list partition

       Partition ###   Type      Size     Offset
       -------------   --------- -------  -------
       Partition 1     Primary   489 GB    32 KB

     DISKPART> select partition 1

     Partition 1 is now the selected partition.

     DISKPART> shrink querymax

     The maximum number of reclaimable bytes is: 40 GB

     DISKPART> shrink desired=32000

     DiskPart successfully shrunk the partition by: 32000 MB

     DISKPART> exit

     Leaving DiskPart...

     C:\>

Deleting a partition, logical drive, or volume removes the associated file system and all associated data. When you delete a logical drive, the logical drive is removed from the associated extended partition and its space is marked as free. When you delete a partition or volume, the entire partition or volume is deleted and its space is marked as Unallocated. If you want to delete an extended partition that contains logical drives, however, you must delete the logical drives before trying to delete the extended partition.

In Disk Management, you can delete a partition, logical drive, or volume by pressing and holding or right-clicking it and then choosing Delete Partition, Delete Logical Drive, or Delete Volume, as appropriate. When prompted to confirm the action, tap or click Yes.