Книга: Windows Server 2012 R2 Storage, Security, & Networking Pocket Consultant

Implementing RAID-5: disk striping with parity

Implementing RAID-5: disk striping with parity

RAID level 5 is disk striping with parity. With this technique, you need a minimum of three hard disk drives to set up fault tolerance. Disk Management sizes the volumes on these drives identically.

RAID-5 distributes data and parity data sequentially across the disks in the array. Fault tolerance ensures that the failure of a single drive won’t bring down the entire drive set. Instead, the set continues to function with disk operations directed at the remaining volumes in the set.

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. (This process, called regenerating the striped set, is covered in “Managing RAID and recovering from failures” later in the chapter.) If two disks fail, however, the parity information isn’t sufficient to recover the data, and you need to rebuild the striped set from backup.

In Disk Management, you can create a striped set with parity by following these steps:

1. In Disk Management’s Graphical View, press and hold or right-click an area marked Unallocated on a dynamic disk, and then tap or click New RAID-5 Volume. This starts the New RAID-5 Volume Wizard. Read the Welcome page, and then tap or click Next.

2. Create the volume as described previously in “Creating volumes and volume sets.” The key difference when creating a striped set with parity is that you must select free space on three separate dynamic drives.

After you create a striped set with parity (RAID-5), users can use the set just like they would a normal drive. Keep in mind that you can’t extend a striped set with parity after you create it; therefore, you should carefully consider the setup before you implement it.

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