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Data Loss

August 10, 2011 - Dave Hecei
It really hits hard when you go to your computer and you see an error message on the screen or you hear a funny noise coming from somewhere. Yes, your hard drive has died. If you have a Macintosh desktop or laptop, unless it’s a MacBook Air with an SSD type drive, you will have a day like this, eventually. It’s a hard thing to take unless you have a good backup plan in place, and you use it. What was on that drive and was it backed up?

There are so many ways to do backups. The problem is that most computer owners never do it. When Apple came out with OS X 10.5, Leopard, they also came out with Time Machine. There are those who cheer it, those who jeer it, but I can say that it is better than nothing. The best part of Time Machine it requires no real setup. Just add an additional hard drive to your Mac, answer yes to the pop-up asking if you want to use this drive for Time Machine, and that’s it. The initial backup will take a little while, but after that, Time Machine will automatically do a backup about every hour, but only the files that have changed since the last backup.

All hard drives will fail. It may happen right away, or it may take several years. The problem is that a hard drive spins. Anything with moving parts is going to fail. I deal with a lot of hard drives at work and at home (I know I’m not the norm since I own several external hard drives). In my experiences, today’s hard drives seem to fail faster than drives of a several years ago. I have some really old Macs that still work today, but those drives held less than 300MB.

I don’t think there is a manufacturing problem, it’s a combination of a few things. First – there are just so many drives made. Computers are everywhere and millions more are made each year. They all need a hard drive – or two, or three. If a company has a failure rate of one percent, then out of a million drives a month there would be 10,000 bad drives. Five years ago that company might of only made 200,000 a month. One percent of that would only be 2,000 drives. The odds are just a bit better that you might get a bad one.

The other problem is density. Drives today are huge. I’m not talking about taking up half you desk, I mean that a typical hard drive has over 1 terabyte of storage. A 2 or 3TB drive is the same physical size as a 200MB drive, which was the more typical size five years ago. The magnetic density of the drive platters is packed so tight that the drive mechanism has to be even more precise than just a few years ago.

So what do we do? The truth is – not much. The best way to deal with important data is redundancy. This means owning more that one hard drive. This means that you will want to have an extra hard drive for every drive you have now. If you have one drive now for your operating system and applications, most likely this is your ‘boot drive’, then you will want another one of the same size to make an exact duplicate. On a Mac there is an excellent drive-mirroring program called Super Duper, and it has a great price – free.

With Super Duper, you just tell it which is the ‘source’ drive and which is the ‘target’ drive. Select the boot drive as your source and your backup drive as the target. It will erase the target drive so make sure that you really want to do that before you say yes. Super Duper will then make an exact copy of the source drive on the target drive. If the source drive is bootable, the target will also be bootable when you are finished.

If you use a second drive on your system to store your data files, or maybe it’s your backup drive, then think about switching that drive to one that has redundancy built in. These are called RAID drives – Redundant Array of Independent Drives. There are different types of RAIDs, but the two types we are interested in are referred to as RAID 1 or RAID 5.

RAID 1 is also called mirrored drives. This is a set of two hard drives. The total amount of storage is equal to just one of the drives (2- 1TB drives in a RAID 1 would give you a 1TB drive). When you write data to a RAID 1 drive, it will write that data to both drives at the same time. You essentially are making a backup as you go. A good RAID 1 system will let you know if a drive has failed, or is about to. Just remove the bad drive and install a new drive of the same size. The system should automatically copy data from the good drive to the new drive for you. After that ‘reconstruction’ is done, the RAID 1 is ready for use again.

RAID 5 is a bit more sophisticated. RAID 5 is usually made up of four identical hard drives. These four drives are combined together to form one big drive. Not all of that space is available as a part of that space is reserved for something called ‘parity’ (4 - 1TB drives add up to 4TB but subtract about 1TB for parity leaving 3TB of storage space). The idea behind RAID 5 is that if one drive fails you just remove it and replace it with a new drive. When a new drive is added back into the RAID 5 system, data from the failed drive can be automatically recreated from the parity information on the other three working drives. RAID 5 is not completely safe, if more than one drive fails at the same time, recovery is not possible.

There actually is a third type of RAID, which isn’t truly a RAID. There is a company that makes some very interesting drive enclosures. I’m talking about Drobo, which is short for Data Robot. Yeah, that’s what I said. This system works similar to a RAID 5 array. The big difference is that you are not limited to four identical drives. With a 4-bay Drobo unit, the base model, you can insert four drives of any size. You could put in a 400MB, a 500MB, and two 1TB drives. These all add up to 2.9TB of data, but part of this is used for redundancy. If you put these same drives in a RAID 5 box, it would see them as four 400MB drives. RAID 5 will see all drives as the size of the smallest drive.

Drobos start with a 4-bay unit and go up to 5, and 8-bay units. They even have models designed more for business use that can hold up to 12 drives, but it is pricey. The 4-bay unit starts at $399, the 5-bay FS is $699, and the 5-bay S is $799. Remember, these are just boxes, they do not come with any drives. For home or home office, or anyone with lots of data, the base Drobo would be just perfect. At $399 (street price less than $350), it is a pretty good deal for a very unique storage solution.

For a more modest home setup, a RAID 1 type drive is ideal. I like the MyBook II from Western Digital. These are two-drive RAID 1 external units that will work with Macs and Windows PCs. They have multiple ports so you can use them with most any computer system. The MyBook II has Firewire 800 or 400, USB 2.0, and ESATA ports. It is available with 1, 2, 4, or 6TB of storage. Street price starts at under $200, and unlike the Drobo, these come with drives installed.

 
 

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