RAID Backup

Working perfectly!

Usually, a person needs a backup when their disk drive fails. All disk drives fail sometime - there is no escape from that truth. But there are other reasons for keeping good backups:

• Total disaster, such as a fire or flood that destroys the whole computer and all nearby backups.
• Deliberate mischief, such as a virus that deletes important files.
• Accidental deletion or modification of one or more files.

I'm sure there are more reasons, but if we cover these we'll probably have the rest covered.

Drive Failure:

Disk drive failure can mostly be avoided by using two mirrored drives in a configuration known as RAID 1. RAID means Redundant Array of Independent Drives, and has several well-defined levels. RAID 1 is a simple comfiguration with two drives which always contain exactly the same information, hence the term "mirrored." If either drive fails, the other simply becomes the system's sole drive and takes over without a hitch. Since the probability of two drives failing at once is very small, RAID 1 pretty well covers that problem. The new computer here employs RAID 1.

Total Disaster:

If the building burns down or floods, the only solution is to have a separate backup stored offsite. This can be on the internet, another building some distance away, or perhaps in a fire- and water-proof safe. At this office a flood is highly unlikely, so we store encrypted DVD backups of most user files in a fire-resistant safe in the basement, and we occasionally put a DVD in a safe deposit box at the bank. I have just set up an upload account and I may stop putting DVDs in the safe deposit box. We'll see.

Deliberate Mischief, or Accidental Deletion or Modification:

RAID disks don't help here, because the RAID disk controller keeps the two mirrored disks identical even when the files themselves are deleted or corrupted. This is where Windows System Restore can be very handy indeed. I have several times seen a serious problem solved by restoring a system to a previous date and time. System Restore works, though it has the disadvantage that the whole drive reverts to a selected time in the past, even if you only need to recover one file.

But if System Restore isn't the solution, then backups are the answer. DVD and internet backups can be used to restore user data, but what about all of the rest of the system? I started a full backup once, but quit when the backup wizard pointed out that I would need 19 DVDs. Enter "RAID Backup" with a third identical disk drive. At some reasonable interval (every day, every week, every month) I can disconnect the power to one of the two mirrored disks and connect the third disk. The disconnected disk is instantly a complete backup of everything, and the newly-connected disk will soon be overwritten and re-mirrored to the remaining good disk in the RAID 1 pair. Voila - complete backup in about five minutes for a one-time cost of about $80. It does actually take about 2 hours and 15 minutes to re-mirror, but the system is usable, if slower, while that takes place. And the third disk, with no power, is safe from any mischief.

It Works!:

I wasn't entirely sure that the Intel software would be totally cool with what I wanted to do, but I tried it last night and today. The system has three identical 320 Mb Western Digital hard disk. Steps in the experiment:

• Disk Drives A and B were mirrored, drive C was powered up as a spare but had never been used.
• I shut down the computer, disconnected power on B, rebooted the computer. The Bios complained that the RAID 1 pair was "degraded" and gave me a chance to deal with it in the Bios, but I declined and let the bootup proceed.
• The computer booted normally, and the Intel monitor software presented a pop-up balloon that said the RAID 1 disk was degraded but could be repaired.
• I clicked on the balloon and followed the instructions to restore disk C to mirror the good disk in the RAID pair, disk A. Two and a quarter hours later, A & C were a mirrored RAID pair and B was a complete backup. Job done.
• As an experiment, however, I shut down again and disconnected all EXCEPT disk B, then rebooted. Again the Bios complained and the on-line software did too, but the system functioned normally on just the "backup" disk. As far as I could tell, all files were accessible. The RAID software, apparently confused, also created a second RAID array at this point, consisting of Disk B and a "missing" disk. Duh.
• I rebooted with only A & C connected, and everything worked once again, no complaints.
• Then I connected B as well, rebooted, and got some complaints about a degraded pair in the second RAID array (disk B), but the system ran normally and all files on all disks seemed to be accessible, including the files on disk B.
• Finally, I disconnected disk C, leaving A & B connected, and rebooted once again. The Bios and the Intel application software both complained about degraded RAID arrays. But it allowed me to delete the second RAID array, consisting of only disk B. That done, it allowed me to re-mirror B to the good disk in the original RAID pair, disk A, even though disk B contained lots of valid data. I was concerned that it might not let me destroy data, and I think there were at least four warnings that data would be destroyed on disk B if I proceeded, but it finally let me do it. Now disk C is again the full backup and the system is back to a RAID array of disks A & B.

From now on the procedure will be much simpler: Shut down, disconnect B or C (whichever was connected), reconnect the disk that was disconnected, reboot, and tell the Intel application to restore the RAID array. The biggest hassle is moving the computer to a position where I can open the side panel and disconnect / reconnect drives. I can handle it.

Windows Experience Index:

Before these little experiments, the system's Windows Experience Index was 5.4, limited by the disk subscore of 5.4. I ran the tests several times. Since the experiments, the Windows Experience Index is 5.5, limited by both the processor and gaming graphics, with the disk subscore improving to 5.7. Why did the disk subscore go up from 5.4 to 5.7, using exactly the same disks? Only Microsoft knows.

Everything is Here

The Intel E6750 Boxed CPU and three Western Digital 320-Gb SATA hard drives arrived today, and now all of the parts are here. I set everything except the case out on the picnic table for a photo. Out of several photos, my sweetie liked this one with fall color in the background :-)

Then I downloaded an Intel video that demonstrates how to install the processor and "thermal solution" (fan + heat sink) on the Intel DP35DP motherboard. After playing the video once, I played it again and did the installation while watching the video. What makes it tricky is that dozens upon dozens of tiny pins on the motherboard socket must match up with a similar number of contact lands on the CPU wafer, without bending any of the pins.

And the CPU is just a wafer at this point, not fragile exactly but the motherboard pins are. You are supposed to set the square wafer straight down on the pins without sliding it at all, but I must admit that when I set it down it wasn't perfectly aligned and it did slide slightly. I hope those pins handled it - I didn't look.

After inserting the wafer you close a little door and then a little spring handle to press the door and wafer down tightly against the socket pins. Then you put the heatsink on top of it all and fasten it down with its own little plastic clips, plug the heatsink fan into the appropriate connector, tie off any spare wire, and job done. I hope. I'll feel a little better when I power it up and get a BIOS screen.

By comparison, the 4 Gb of G.Skill RAM seemed quite easy to install. Just push it carefully into the socket.

On another note: My first experience with computers was in 1962, 45 years ago, when disk drives were barely on the horizon. We used a magnetic tape operating system, and wrote programs on punched cards or paper tape. Later, about 28 years ago, I bought my first computer while working at 3M, with 64 Kb of RAM (yes RAM, not core), and a 5-Mb disk drive which was too heavy for one person to manage alone. These palm-sized disks each have 64,000 (sixty-four thousand) times as much disk capacity, and the CPU will enjoy 62,500 times as much RAM. Oh, and the RAM is about 800 times faster, while the CPU is easly 2500 times faster and there are two in the chip. Isn't technology stunning?

Gateway Performance 600

I'm struggling with the original precept of this blog: building a new computer, because my Gateway Performance 600 is working so well now. It's almost eight years old, but it runs a Pentium III processor at 600 MHz and has been upgraded significantly:

1. Added another hard disk to increase total disk capacity from 20 Gb to about 100 Gb.
2. Replaced the original CD RW drive (failed) with a new and better Sony drive.
3. Upgraded from Windows 98 to Windows XP Professional, now SP2 and fully current.
4. Maxed out the memory to 768 Mbytes, comparable to brand-new low-end computers.

It's not a bad computer, and I'm wavering on the decision to replace it. Money ($1000+) and time are the reasons NOT to replace it. Here are some reasons why I might:

• Quieter. The Performance 600, though not loud, is the loudest thing in the room.
• Faster. I wonder how much. The processors will be ten or twenty times as fast and the disk(s) at least twice as fast. I'm sure the difference will be noticeable!
• Upgradable. In theory at least, the memory will be upgradable to 8 Gb.
• Bigger disk. At least three times as much, upgradable to much more.
• Windows Vista or Vista compatible. The Gateway 600 is not even slightly compatible with Vista, needing more speed, disk, a DVD drive, and more.
• More reliable? Only the CD RW drive in the 600 has ever failed, but I've been lucky because hard disks certainly do fail too. I'm thinking about paired disks in the new computer for improved data security, and a better backup system than the zipped CD ROMs I use now.
• Experience. Mine. I will enjoy the experience and learn a LOT! I've been involved in computers almost all of my adult life (45+ years) and it's time to add some current technology to that knowledge.

I'm almost convinced, but then again the 600 is really working pretty well. I have plenty of time to think about it.

RAID

RAID is a computer acronym meaning "Redundant Array of Independent Disks." Wikipedia. In this case we're talking about "mirrored" disks, one of the simplest RAID configurations, where two identical disks contain identical data so that one can continue operating if the other fails. Since they contain the same data the second disk doesn't add any disk capacity, but it does add reliability. Pros:

• The hard disk is MUCH less apt to crash. Only people who have experienced a crash can fully appreciate this.
• Perhaps I can get away with less backup, e.g. only back up the most sensitive data.
• Or, I can buy a THIRD drive and hot-swap it, so the swapped-out drive is the backup.
• I'd enjoy the experience of setting it up and using it.

Cons:

• It's more expensive: I need two drives, not one, and the motherboard (which manages the drives) costs a little more.
• The drives will make twice as much noise. Hmmm.
• It doesn't solve ALL backup problems: If I accidentally permanently delete a file, it will be gone on BOTH drives; if lightning hits the computer it could easily take out both drives.

I'm leaning toward RAID, as you may have guessed. But haven't decided yet for sure. Seems like overkill for a simple office computer. But then again there's the experience of it ...

Here are some other features of the computer that's starting to come together:

• Sonata III 500 case, with 500 W power supply. This is the outer box for the whole thing, and this box is quiet with plenty of power available.
• Intel E6750 dual-core processor, 2.66 GHz, 1333 front-side bus, with Intel motherboard to match. This is two very fast processors in one. By the time I get going on this, the E6850 may come down in price, even faster.
• 2 Gb of 2-channel DDR2 memory, 800 MHz. Expandable to 8 Gb they say, but the chips for that don't exist yet; 4 Gb is the max.
• Seagate 320 Gb SATA-300 drive(s). Big enough for me.
• Sony AWG170S-B2 18x DVD read/write.

But everything is still in pencil. Absolutely everything. Meantime, though, I did a little pricing of the materials lists for WITH RAID and withOUT RAID. Here are very preliminary materials lists:

• With RAID.
• Without RAID.

I'm totally new at this, a complete novice. If there is anyone out there reading this blog with an idea or a word of caution, I'd love to hear from you.