Resizing partitions and volumes
Windows Server 2012 R2 doesn’t use Ntldr and Boot.ini to load the operating system. Instead, Windows Server 2012 R2 has a preboot environment in which Windows Boot Manager is used to control startup and load the boot application you selected. Windows Boot Manager also finally frees the Windows operating system from its reliance on MS-DOS so that you can use drives in new ways. With Windows Server 2012 R2, you can extend and shrink both basic and dynamic disks. You can use Disk Management, DiskPart, or Windows PowerShell to extend and shrink volumes. You cannot shrink or extend striped, mirrored, or striped-with-parity 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 from 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.
CAUTION 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. You can’t extend striped volumes, volumes that aren’t formatted, or volumes that are formatted with FAT. Additionally, you can’t extend a system or boot volume, regardless of its configuration.
You can shrink a simple volume or a spanned volume by following these steps:
1. In Disk Management, press and hold or right-click the volume you want to shrink, and then tap or click Shrink Volume. This option is available only if the volume meets the previously discussed criteria.
2. In the box provided in the Shrink dialog box, shown in Figure 2–9, enter the amount of space to shrink.
FIGURE 2–9 Specify the amount of space to shrink from the volume.
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 the volume can be shrunk. 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’ll want to ensure that the drive 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 will be (in megabytes) after the shrink. This is the new formatted size of the volume.
3. Tap or click Shrink to shrink the volume.
You can extend a simple volume or a spanned volume by following these steps:
1. In Disk Management, press and hold or right-click the volume 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 dynamic disks.
2. In the Extend Volume Wizard, read the introductory message, and then tap or click Next.
3. 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 are automatically selected. By default, all remaining free space on those disks is selected for use.
4. With dynamic disks, you can specify the additional space you want to use on other disks by performing the following tasks:
■ 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, in the Select The Amount Of Space In MB list, specify the amount of unallocated space to use on the selected disk.
5. Tap or click Next, confirm your options, and then tap or click Finish.
Repairing disk errors and inconsistencies automatically
Windows Server 2012 R2 includes feature enhancements that reduce the amount of manual maintenance you must perform on disk drives. The following enhancements have the most impact on the way you work with disks:
■ Transactional NTFS
■ Self-healing NTFS
Transactional NTFS allows file operations on an NTFS volume to be performed transactionally, which means programs can use a transaction to group sets of file and registry operations so that all of them succeed or none of them succeed. While a transaction is active, changes are not visible outside the transaction. Changes are committed and written fully to disk only when a transaction is completed successfully. If a transaction fails or is incomplete, the program rolls back the transactional work to restore the file system to the state it was in prior to the transaction.
REAL WORLD Resilient File System (ReFS) takes the transactional and self-healing features of NTFS a few steps further. With ReFS, several background processes are used to maintain disk integrity automatically. The scrubber process checks the disk for inconsistencies and errors. If any are found, a repair process localizes the problems and performs automatic online correction. In the rare case that a physical drive has bad sectors that are causing the problem, ReFS uses a salvage process to mark the bad sectors and remove them from the file system-and all while the volume is online.
Transactions that span multiple volumes are coordinated by the Kernel Transaction Manager (KTM). The KTM supports independent recovery of volumes if a transaction fails. The local resource manager for a volume maintains a separate transaction log and is responsible for maintaining threads for transactions separate from threads that perform the file work.
Traditionally, you had to use the Check Disk tool to fix errors and inconsistencies in NTFS volumes on a disk. Because this process can disrupt the availability of Windows systems, Windows Server 2012 R2 uses self-healing NTFS to protect file systems without requiring you to use separate maintenance tools to fix problems. Because much of the self-healing process is enabled and performed automatically, you might need to perform volume maintenance manually only when you are notified by the operating system that a problem cannot be corrected automatically. If such an error occurs, Windows Server 2012 R2 notifies you about the problem and provides possible solutions.
Self-healing NTFS has many advantages over Check Disk, including the following:
■ Check Disk must have exclusive access to volumes, which means system and boot volumes can be checked only when the operating system starts up. On the other hand, with self-healing NTFS, the file system is always available and does not need to be corrected offline (in most cases).
■ Self-healing NTFS attempts to preserve as much data as possible if corruption occurs and reduces failed file system mounting that previously could occur if a volume was known to have errors or inconsistencies. During restart, self-healing NTFS repairs the volume immediately so that it can be mounted.