Hard drive storage is great for most backup purposes.
Not only is it cheaper than other media like DVD, but its read/write speeds make it the ideal solution for lightning fast recovery in a pinch. And it’s getting cheaper all the time.
Also, it’s an extremely dense way to store data, which makes it ideal for conserving space in an already over-crowded datacenter.
And of course, nothing beats disk when it comes to speed. Disk gives you random access to your data, which makes it more convenient than tape when it comes to finding specific files of interest.
But hard drives also have some other issues that you should keep in mind.
First of all, disk is very unstable. If a part of the disk fails, you’re very likely to lose all of your data. Contrast this with tape storage, where damage to one part of the tape is very unlikely to destroy the data on the rest of the device.
Second of all, disk drives are complicated devices which contain many moving parts. When stored over long periods of time, there’s an increased chance that these parts will deteriorate and cause the device to be completely unreadable. Once again, contrast this with the way tape separates the storage media from the reading devices.
Finally, unlike tape, hard drives are not built to be reverse compatible. If you store a drive for 10 years, there’s a good chance that the adapters and drivers for the device will become obsolete over time. This means that your data will be trapped forever unless you can somehow locate a reading device that supports your format.
To make matters worse, these risks compound with scale. As the number of disks and the age of the archives continue to grow, so does the chance of potential data loss.
If you enjoy the speed and convenience of disk for backup, keep using it. But if you plan on storing these backups for longer periods of time, you may want to consider adding other types of backup media to the mix.
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