[Editor's Note: Solve this month's Windows NT problem and get the chance to win $100 or a copy of one of the author's books about NT. Email your solutions to challenge@winntmag.com. Include your full name, mailing address, and connection to NT (e.g., administrator, user). To add to the author's collection of NT problems, email problems and solutions to answers@voicenet.com. Look for the solution to this month's problem in the October issue.]
Problem
Eclectic Autos' IS department needs to upgrade its hardware. The Spit and Polish division's Windows NT 4.0 server needs upgrading. This server holds two databases: the database the spitters and polishers use to look up suppliers, part numbers, and prices, and the database in which they enter details about each job they perform. The computer is also the department's (Microsoft Exchange) email server.
The spitters and polishers are concerned about the database's accessibility and integrity, and they're especially worried about email problems. The IS codirectors, Larry and Moe, have a budget that isn't large enough to cover everything they want. Larry and Moe agree that their system must be reliable (i.e., fault tolerant), but they can't agree on how to best achieve reliability. Larry prefers mirror sets, and Moe insists on stripe sets with parity.
One of Larry and Moe's arguments follows. See how much misinformation you can identify.
Larry: Mirror sets are faster because they write the data set whenever they have a free nanosecond. Mirror sets need only two disks, whereas stripe sets with parity need at least four disks.
Moe: But stripe sets with parity are perfect for high-speed data writing because they write symmetrically. Our email server has periods of high-speed writing and not much reading, so stripe sets with parity are a perfect solution for our server.
Larry: If we use mirror sets we can use the disks in the storage room.
Moe: No we can't, because mirror sets require identical disks, and the disks in the storage room are not identical.
Larry: Wrong; the disks don't have to be identical.
Moe: You're wrong. Besides, if we use stripe sets with parity, we can easily add disks to enlarge the stripe sets if we need more disk space.
Larry: Let's compromise. We can install six disks, using four disks we have. Thus, we'll need to purchase two disks, but they don't need to be large, expensive disks. The first four disks will be stripe sets with parity, and the last two disks will be a mirror set.
Moe: You can't boot from stripe sets with parity, so the system files need to be on the first two disks, which must be mirror sets.
Larry: OK, but we need to put the swap file on the stripe set with parity because it has more available disk space.
Which elements of this conversation are incorrect? The more mistakes you catch, the better chance you have to win the prize.