One of my favorite computer technicians, Dave Brooks, reveals what’s really inside that mega Hard Drive you were thinking of buying.
Numerous articles have appeared here on Bill’s blog about how important data backup is. This article will not discuss the why’s; it will discuss an issue which I feel is a trend in the external enclosure industry, a very bad trend, and not always disclosed in a products description.
When shopping for an external hard drive for backup purposes, you need to be aware of the following issue.
The average consumer would think that when buying a 1 or 2TB external hard drive, the enclosure contains a 1 or 2 TB hard drive, but that isn’t so on some Lacie and some other manufacturers’ enclosures.
They may actually contain 2 physical hard drives, half the size of the total capacity, set up in a striped RAID array. With the electronics inside the enclosure controlling the drives, your system will see a 2TB drive, but the enclosure actually contains 2 1TB drives.
The problem with these is, if one of the 2 drives fail, all your data is lost if the electronics board in the enclosure fails all of your data is lost. In a normal single disk enclosure it’s usually possible to remove the drive from the enclosure to get data off of it, if the enclosure electronics or power supply fails.
This striped array method is absolutely the worst way to store important data, as it doubles the possibility of hard drive failure and data loss. Any IT person worth his salt will never recommend this setup for storing critical data (unless there is a backup of the backup done on a regular basis).
I’ve had 2 customers with Lacie enclosures set up this way. One had the electronics board in the enclosure fail, and data recovery was not possible via any methods I had -even going so far as to use a Linux box and data recovery software designed to reassemble RAID disks into a single image. The only option was to send the drives to a data recovery specialist at the cost of hundreds to even thousands of dollars.
The second customer had one of the drives fail (multiple bad blocks), and believe it or not, this is actually the better failure scenario, as I was able to repair the drive to get it working in the enclosure.
The recovery of almost 1Tb of data was successful – he got lucky, and saved a bunch of money as I don’t charge anywhere near what professional data recovery companies do, but they have techniques and equipment I can only dream about 🙂
The place for this type of RAID setup is when higher performance is desired. A striped array of two 500GB drives (that gives 1TB of useable storage) is faster than a single 1TB drive. I use this setup in my gaming PC, but it must be backed up on a regular basis.
Just keep this info in mind when shopping for that next external backup drive!
Guest Writer: This is a guest post by Dave Brooks a professional computer technician from New Hampshire, USA. Dave has become a regular guest writer, who’s articles are always a huge hit.
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