| Previous | Table of Contents | Next |
Creating a stripe set with parity is much less complex than a mirror set, mostly because a stripe set cannot be used for the system partition. Because a stripe set can never be used for a bootable partition, the problems associated with the boot sector are not relevant. What is relevant is that the information to access the stripe set with parity is contained in the system registry located on your system partition. If you have a catastrophic failure of the system partition and have to install another copy of Windows NT Server, you will be unable to access your stripe set with parity volume. And that is a serious problem!
Yet, if you plan carefully, you can eliminate this problem. First, you can make regular backups of the system partition to tape. At the time you make the backup, you can copy the registry to tape, as well, by enabling the Backup Local Registry checkbox. Secondly, you can use the Disk Administrator to save your System registry hive to a floppy using the Partition|Configuration|Save menu command. Finally, you can use RDISK.EXE—the repair disk utility—to update the compressed repair information stored in the SystemRoot\Repair subdirectory and create a new emergency rescue disk.
Unfortunately, as your system grows, you’ll most likely find that your system registry or complete set of registry files will no longer fit onto a single floppy. Therefore, using the repair disk utility or the disk administrator to save this information to a floppy will be impossible. Fortunately, you can usually copy the compressed repair information to a floppy or another disk drive. I use my Zip drive to store this information. You can store it compressed or uncompressed. To uncompress the files, use the EXPAND.EXE command located in your SystemRoot\System32 subdirectory. To expand the compressed system registry hive, you can use the following command (where G: is the drive letter to copy the decompressed file to):
EXPAND %SystemRoot\Repair\System._ G:\system.
Then after reinstalling Windows NT Server, you can use the Disk Administrator’s Partition|Configuration|Restore menu command to restore your access to the stripe set with parity volume.
Backing up your system registry hive applies to mirror sets as well. It is always a good idea to back up your system registry whenever you make a change to your disk configuration, because you never know when you might need it.
So, now that we have discussed a few of the problems you might encounter and how to resolve them, you can follow the steps presented here to create a stripe set with parity:
Note: A stripe set with parity requires a minimum of 3 volumes and a maximum of 32 volumes.
Once more, you will be reminded to update your configuration information on your emergency repair disk or create a new emergency repair disk. Then, the stripe set with parity will be established but not actually generated until you have rebooted the server. Once you have restarted the system, you can format the partition. Using Disk Administrator in Volumes view, the status should read Healthy and remain that way until a failure occurs. If the volume is large enough and takes a long time to actually build, the status might read Initializing until the entire volume has been generated.
This concludes our discussion about installing mirror sets and stripe sets with parity. Now, let’s look at ways to recover your data if your redundant disk system fails.
Should you have a failure on a redundant disk system or fault tolerant partition, your next step should be to either get your server up and running using the slave partition of your mirror set, or recover the data on your stripe set with parity volume. But, you do not have to perform this task immediately. You can wait a short time until it is convenient to take the server down to effect the repairs. In the case of an immediate failure of a mirror set where you must reboot the server, you can do so using a startup disk. Creating this startup disk takes a little work and a bit of understanding of some of the Windows NT Server boot files. So, pour yourself a cup of coffee—to help you stay awake—and let’s get to work building a startup disk specifically tailored to your system.
Note: The following section applies specifically to Windows NT operating on an Intel x86 processor. For RISC processors, I suggest you refer to the Windows NT Server reference guide, because it contains detailed instructions on how to create a startup disk for various RISC platforms.
| Previous | Table of Contents | Next |