This is the next tutorial in the series on drive management under Windows 2000 Server intended to accompany the modules, classroom lectures and exercises of the Microcomputer Service and Maintenance 3 course.
Before performing the procedures of this tutorial be sure to complete the preparations and procedures of the Write Signature and Dynamic Disk Upgrade Wizard tutorial. Then proceed to the procedures below to create the RAID-5 Data Drive Set.
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Disk Manager is a GUI tool that has the power of FDISK and FORMAT and beyond. It is capable of constructing RAIDs on IDE channels as well as SCSI channels that are implemented by the Windows 2000 operating system itself as opposed to a hardware RAID card that implements the RAID at the circuitry/BIOS level of the card. Hardware RAIDs are far superior and should be the only choice in mission critical servers, but the software level RAIDs that Windows 2000 can implement do add more protection to valuable data than not implementing them at all. Disk Manager (DM) is a snap-in to the Microsoft Management Console (MMC) applet of the Control Panel. Open Start > Programs > Administrative Tools > Computer Management to open the MMC:
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Clicking on this Start Menu item open the Computer Management console which looks like this:
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With it open click the Disk Management folder far down the left hand side. In this exercise, three harddrives have already been added to the system and had signatures written to them and they have also been upgraded to dynamic disks. Both procedures are necessary before the drives can be used to create a RAID-5 volume across them. See Write Signature and Upgrade Disk Wizard.
A RAID-5 Volume will require a minimum of three physical drives in order to function. Each drive must have an equal amount of space available that will participate in the RAID-5 volume. Even though the drives do not have to be identical and the RAID partitions can share available space on the drives with other partitions this is not recommended. That is, all drives should be identical and the only partitions on each of these disks should be the RAID-5 partitions contributing to the RAID-5 volume.
A RAID-5 volume is defined as a system of data storage involving at least three independent physical drives in which data will be stored on them by spanning the data across the disks. The term used is: Distributed striping with parity. In this a file will be split in half. Half of the the data will be written to Disk #1, half will be written to Disk #2, and a parity block of data will calculated from these two halves of data and that will be written to Disk #3. In the event that either Disk #1 or Disk #2 should fail and be unreadable, the other half of the file can be read, and then the parity block on Disk #3 can be used to reconstruct the other half of the file that is inaccessible. This allows the RAID-5 to continue providing data even though one of the pghysical drives has crashed. This is in fact the reason that a RAID-5 is used. This ability for the system to continue functioning even when a piece of hardware has failed is called fault tolerance. The fact that some of the data storage capacity is consumed by parity information rather than actual data is called redundancy which means that the parity data is no more than a repetition (in coded form) of the original files. Now the RAID-5 can be created. Having opened the Disk Manager (DM) with all of the drives prepared, right click on the "unallocated space" of the first disk that will be used for the RAID-5. Click on the Create Volume choice of the popup menu:
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This opens the Create New Volume Wizard which starts like this:
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Click the Next button and the Select Volume type screen appears. Select RAID-5:
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Click the Next button and then in the new panel of the wizard, single click on Disk 1 and then click the Add button. Do the same for Disk 2 and for Disk 3:
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Click the Next button and select "Assign a Drive Letter" and set the letter to R:
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Click the Next button and then Select Format the Volume, file system to use should be NTFS, allocation unit size should be "Default," Volume Label doesn't matter, place a check in Quick format (though you should full format in practice, since it does a moderately useful error checking of the surface integrity of the drives):
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Click the Next button and the Summary of the operation is displayed at the end of the Create New Volume Wizard. Look over the choices and confirm the operation activities then click the Finish button:
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At this point the wizard closes and the new partitions that will hold the volume are created and marked in the default color of teal, the messages in each partition indicate that DM is "Regenerating" the volume. This process should not be interupted.
Shortly after the above screen the messages change to "Formatting x%" progress indicators. When the formatting is complete this screen will will look like the one below. Note: The "Regenerating" and "Formatting" messages appear where the message "Healthy" is now displayed:
Testing the RAID-5 Volume and Recovering from "Damage"
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Now that the RAID-5 has been created successfully we will intentionally damage it in order to test its abilities to safeguard data and learn how to recover from the loss of one of the drives of the RAID-5 Data Drive Set.
Working complete PC