Power failures and system crashes do happen and can corrupt both active and idle files and turn your system to an inconsistent state. Although, Windows 7 NTFS can roll back the uncommitted transactions and returns the file system to a consistent state, you might still need to scan the entire file system for errors.
In simple terms, a mirrored volume (RAID-1) writes the same data on two disks or partitions of separate disks. That is, any changes to data (or new data) made to the first disk of the mirror set are also made to its mirror disk. Mirrored volumes require at least two disks or two free partitions on separate disks. The free partitions or disks need to be of the same size, otherwise, the mirrored volume size would be equal to the smallest partition or disk.
The main advantage of mirrored volumes is disk drive redundancy. It provides availability of data in case one disk drive fails while it can mirror a system disk containing the operating system. If a disk fails, the mirror set continues to operate on the remaining disk. The recovery operation of the mirror set depends on which disk fails if the set contains the system disk. In general you would break/remove the mirror set, replace the faulty disk and re-create the set.
A striped volume (RAID-0) writes data in small blocks or stripes on two or more disks simultaneously. To create a striped volume you require at least two disks, however, having more than two disks participating in the striped volume will enhance further data access performance. That is, when data is written or read from a set of disks simultaneously the I/O bandwidth increases and hence, achieving better read and write transfer speeds. When creating a striped volume, the volume size is dependent on the disk with the smallest free space, as the portions of the disks included in the set need to be of the same size. I suggest to use full disks of the same size when creating striped volumes, otherwise, you end up with free spaces on some disks! While, the disks of a striped volume need to be converted to dynamic, remember that such volume is not fault-tolerant. If one disk fails, the entire volume fails.
As most standard Windows installations format the entire disk with one partition or volume (excluding the hidden 100MB system partition), creating additional partitions without installing a new hard disk requires you to resize or better to shrink your existing volume. In certain computer setups, one would be better off with two or more partitions rather than having one large volume (sometimes referred to as the boot drive or the c: local disk). A typical case might be when creating a partition that hosts backups. Usually, backups are large files that take plenty of hard disk space and may halt your system because after so many jobs no free space may be left available for the system to operate. Also, it is by far more simpler to resize an existing volume rather than backing up all data, deleting and re-creating two or more partitions when your system is already installed.
To shrink a volume using Disk Management, perform the following procedure:
- Open the Disk Management console by typing disk management in the Search text box from the start menu, and click the Create and format hard disk partitions link
- From the Disk Management console, right-click the volume you want to shrink and click Shrink volume – the system checks and discovers the maximum available shrink size.
- From the Shrink dialog box specify the amount which you want to shrink the volume or leave the displayed value to shrink to the maximum amount
- The shrink process proceeds without further prompting and at the end you should be able to see a new unallocated space. Then, prepare this newly created space as a new volume.
- To revert back before you prepare the new volume you can right-click the shrinked volume and click Extend Volume and follow the Welcome to the Extend Volume Wizard