This tutorial measures and illustrates the difference in speeds between different RAID levels. These tests apply to both SSD and HDD RAIDs. It also makes clear which RAID level you should use for your storage.
RAIDs can be formatted into different RAID “levels.” For example, RAID 0, 1, 4, 5, 6 and 1+0. Which you choose balances three factors:
The more protection, the slower the speed and the lower the storage capacity. There’s no “right” answer, just the answer that works best for you. Like most of tech, each choice is a tradeoff.
NOTE: Here’s an article that describes each RAID level in a bit more detail.
Recently, I purchased an OWC Thunderblade. This is a 4-drive NVMe SSD RAID which can be configured into any of these RAID levels, except RAID 6. (RAID 6 is specifically designed for HDD RAIDs. It provides protection in case two HDD drives die at the same time. This is not a practical format for SSD RAIDs.)
Here are the results. Results are displayed as a percentage because actual speeds will vary based upon the number of drives, how they are connected, the speed of your computer and a few other factors. However, the relationship between these different formats will remain roughly the same.
NOTE: RAIDs with more than four drives will have faster results for RAID levels 4 and 5, but RAID 0 will always be the fastest.
NOTE: Red bars indicate the theoretical speeds for reading and writing. Green bars indicate actual real-world results. All RAIDS were formatted using OWC SoftRAID.
Reads are always faster than writes. And, while none of the numbers perfectly matched the theory, they were all reasonably close.
For maximum speed, choose RAID 0. If you are worried about losing a drive choose RAID 4 for SSD RAIDS, or RAID 5 for HDD RAIDs, but there is a tradeoff in terms of both speed and storage capacity.
However, given the cost of SSD drives, it is cheaper to format the RAID as RAID 0, then buy an inexpensive hard drive equal to the size of the SSD RAID and backup your data every night to that stand-alone HDD.
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