Table 1.4 breaks down the various aspects of the supported RAID types in Window Server 2012 R2.
TABLE 1.4 Supported RAID-level properties in Windows Server 2012 R2
Creating RAID Sets
Now that you understand the concepts of RAID and how to use it, you can look at the creation of RAID sets in Windows Server 2012 R2. The process of creating a RAID set is the same as the process for creating a simple or spanned volume set, except for the minimum disk requirements associated with each RAID type.
Creating a mirrored volume set is basically the same as creating a volume set, as shown in Exercise 1.6, except that you will select New Mirrored Volume. It is after the disk select wizard appears that you’ll begin to see the difference. Since a new mirrored volume is being created, the volume requires two disks.
During the disk select process, if only one disk is selected, the Next button will be unavailable because the disk minimum has not been met. Refer to Figure 1.3 to view the Select Disks page of the New Mirrored Volume Wizard during the creation of a new mirrored volume, and notice that the Next button is not available.
FIGURE 1.3 Select Disks page of the New Mirrored Volume Wizard
To complete the process, you must select a second disk by highlighting the appropriate disk and adding it to the volume set. Once the second disk has been added, the Add button becomes unavailable, and the Next button is available to complete the mirrored volume set creation (see Figure 1.4).
FIGURE 1.4 Adding the second disk to complete a mirrored volume set
After you click Next, the creation of the mirrored volume set is again just like the rest of the steps in Exercise 1.5. A drive letter will have to be assigned, and the volume will need to be formatted. The new mirrored volume set will appear in Disk Management. In Figure 1.5, notice that the capacity of the volume equals one disk even though two disks have been selected.
FIGURE 1.5 Newly created mirrored volume set
To create a RAID-5 volume set, you use the same process that you use to create a mirrored volume set. The only difference is that a RAID-5 volume set requires that a minimum of three disks be selected to complete the volume creation. The process is simple: Select New RAID-5 Volume, select the three disks that will be used in the volume set, assign a drive letter, and format the volume. Figure 1.6 shows a newly created RAID-5 volume set in Disk Management.
FIGURE 1.6 Newly created RAID-5 volume set
Mount Points
With the ever-increasing demands of storage, mount points are used to surpass the limitation of 26 drive letters and to join two volumes into a folder on a separate physical disk drive. A mount point allows you to configure a volume to be accessed from a folder on another existing disk.
Through Disk Management, a mount point folder can be assigned to a drive instead of using a drive letter, and it can be used on basic or dynamic volumes that are formatted with NTFS. However, mount point folders can be created only on empty folders within a volume. Additionally, mount point folder paths cannot be modified; they can be removed only once they have been created. Exercise 1.6 shows the steps to create a mount point.
EXERCISE 1.6: Creating Mount Points
1. Open Server Manager.
2. Click and then expand Storage.
3. Select Disk Management.
4. Right-click the volume where the mount point folder will be assigned, and select Change Drive Letter And Paths.
5. Click Add.
6. Either type the path to an empty folder on an NTFS volume or click Browse to select or make a new folder for the mount point.
When you explore the drive, you’ll see the new folder created. Notice that the icon indicates that it is a mount point.
Microsoft MPIO
Multipath I/O (MPIO) is associated with high availability because a computer will be able to use a solution with redundant physical paths connected to a storage device. Thus, if one path fails, an application will continue to run because it can access the data across the other path.
The MPIO software provides the functionality needed for the computer to take advantage of the redundant storage paths. MPIO solutions can also load-balance data traffic across both paths to the storage device, virtually eliminating bandwidth bottlenecks to the computer. What allows MPIO to provide this functionality is the new native Microsoft Device Specific Module (Microsoft DSM). The Microsoft DSM is a driver that communicates with storage devices – iSCSI, Fibre Channel, or SAS – and it provides the chosen load-balancing policies. Windows Server 2012 R2 supports the following load-balancing policies:
Failover In a failover configuration, there is no load balancing. There is a primary path that is established for all requests and subsequent standby paths. If the primary path fails, one of the standby paths will be used.
Failback This is similar to failover in that it has primary and standby paths. However, with failback you designate a preferred path that will handle all process requests until it fails, after which the standby path will become active until the primary reestablishes a connection and automatically regains control.
Round Robin In a round-robin configuration, all available paths will be active and will be used to distribute I/O in a balanced round-robin fashion.
Round Robin with a Subset of Paths In this configuration, a specific set of paths will be designated as a primary set and another as standby paths. All I/O will use the primary set of paths in a round-robin fashion until all of the sets fail. Only at this time will the standby paths become active.
Dynamic Least Queue Depth In a dynamic least queue depth configuration, I/O will route to the path with the least number of outstanding requests.
Weighted Path In a weighted path configuration, paths are assigned a numbered weight. I/O requests will use the path with the least weight – the higher the number, the lower the priority.
Exercise 1.7 demonstrates the process of installing the Microsoft MPIO feature for Windows Server 2012 R2.
EXERCISE 1.7: Installing Microsoft MPIO
1. Choose Server Manager by clicking the Server Manager icon on the Taskbar.
2. Click number 2, Add Roles And Features.
3. Choose role-based or feature-based installation and click Next.
4. Choose your server and click Next.
5. Click Next on the Roles screen.
6. On the Select Features screen,