External USB disks are invaluable when you run out of storage space on your laptop or computer but while they offer an easy way to expand your storage they also suffer from various types of failure and are easily susceptible to damage. In the last few years the cost of newer types of Solid State Disks have brought a new range of USB external SSD’s to the market. These disks are more expensive compared to their older (slower) mechanical counterparts, but they do also have some drawbacks that are worth considering when looking at either option.
Key consideration when choosing between mechanical disks and SSD for external storage.
Choosing between external USB mechanical disks and SSDs depends on your specific needs and priorities. If budget is a primary concern and you need large storage capacities, mechanical disks offer a cost-effective solution. However, if you require fast performance, reliability, and durability, especially for portable use, SSDs provide a superior choice despite their higher cost. Understanding these differences, including data recovery capabilities, will help you make an informed decision based on your storage requirements and usage scenarios.
If the data is critical keep more than one backup
It’s an easy recommendation to make but one often easy to forget in practice. Where data is of significant importance its highly advisable to keep multiple backups. This can be frustrating and sometimes time consuming to manage but as with any electrical product its important to remember hard disks of any type can and do fail so for that reason be it a second hard disk or an online backup to Google Drive or Dropbox is important to remember to keep a second backup of anything important whenever possible.
Portable vs Desktop Disks
If you’re looking for long term storage and don’t often need to move a hard disk around its well worth opting for the larger type of desktop external hard disks (which require separate power supplies) the principle being that while the smaller portable hard disks are convenient, they’re also miniaturised versions of their desktop counterparts. This means that components are smaller and more fragile and often the storage density on the surface of the platter of the physical disks is higher, leading to a situation where even the small atomic imperfections in manufacturing or damage through use represent larger amounts of data being potentially lost. For this reason desktop hard disks and generally more reliable if not only for the reason that since they spend most of their time stationary they are also less likely to be subject to drop damage.
Not all disks are built alike
This is true for both portable SSD’s and mechanical disks. While there is a great range of disks available, not all are manufactured to the same specification. Hard disk manufactures offer both premium models and economy models each with different life expectancies.
MTBF (Mean Time Between Failures) values for hard disks can vary based on manufacturer, model, and usage conditions. Below is a table with approximate MTBF values for some common 2.5-inch and 3.5-inch hard disks from reputable manufacturers:
| Form Factor |
Manufacturer |
Model |
MTBF (Hours) |
| 2.5-inch |
Seagate |
BarraCuda 2.5″ |
1,000,000 hours |
| 2.5-inch |
Western Digital |
WD Blue 2.5″ |
600,000 hours |
| 2.5-inch |
Toshiba |
MQ04 2.5″ |
600,000 hours |
| 3.5-inch |
Seagate |
BarraCuda 3.5″ |
1,000,000 hours |
| 3.5-inch |
Western Digital |
WD Blue 3.5″ |
1,000,000 hours |
| 3.5-inch |
Toshiba |
P300 3.5″ |
600,000 hours |
MTBF values are typically estimates provided by manufacturers and should be considered as general indicators rather than precise predictions. However these values along with any given warranty coverage do give some level of expected lifespan for a given disk. The problem with external hard disks is that as consumers we often don’t actually know what hard disk is contained within the plastic assembly we’re purchasing.
One solution to this problem and a good option for those looking to purchase the most reliable disk available is to purchase a hard disk enclosure and the actual hard disk separately. For example the Western Digital Gold Series of disk is backed by a 5 year warranty and a 2.5 million hour MTFB rating. Paring such a disk with a third party USB enclosure means you know exactly what disk you’re using and you can avoid using cheaper less reliable disks. You might also want to check our blog post here on Backblaze’s Drive Stats (another excellent resource)
