SSD vs. HDD: when to choose one over the other

From our archive. Specifics such as products, prices and deadlines reflect the original publish date.

At Advanced Clustering, we hear a lot of opinions for the use of both solid state drives (SSDs) and standard hard disk drives (HDDs), and each has its own pros and cons depending on what their use will be. While there are advantages and disadvantages to each one, the top considerations when deciding between the two are capacity, cost, reliability, and speed.

Spinning disks are currently available in 500GB, 1TB, 2TB, 3TB, and 4TB sizes on the SATA side, with , while SSDs much less storage space, starting at 60GB and going up to 512GB. For purposes of this discussion, we’re sticking with SATA SSDs, as opposed to PCIe-based SSDs. Now, there are larger SATA SSDs, but they are considerably more expensive and in shorther supply due to lower demand, thus we did not include them either in our testing.

Another consideration in drive choice is reliability. Advanced Clustering offers SSDs with a five-year warranty. One question customers often ask is, “if the drive reaches its read/write limit within that five-year period, is it still covered under the warranty?” The answer is yes, it is. SSDs have no moving parts to wear out since they use integrated circuits similar to memory chips, so if an SSD fails, data can still be retrieved and copied to the new drive. On an HDD, however, once the drive fails, data is lost; this is why we usually recommend a RAID configuration for HDDs that hold important data. Today storage is relatively inexpensive. On an HDD drive for example it could cost $0.10 to $0.15 cents per GB depending on the size of the drive and that is one solid advantage to using the HDD. By comparison the SSD has cost ranging from $0.80 to $1.50 per GB. Simply examining cost per gigabyte is a nice metric, but it is often important to measure cost per MB/s. This discussion centers around high performance computing, so while cost is important, performance tends to rule the day. The drives we tested and how they compared:

What we measured:

• 512GB SSD: 584 MB/s read, 551 MB/s write, $469 per drive ($0.92 per GB, $0.41 per MB/s)
• 256GB SSD: 650 MB/s read, 551 MB/s write, $230 per drive ($0.90 per GB, $0.19 per MB/s)
• 128GB SSD: 646 MB/s read, 362 MB/s write, $130 per drive ($1.02 per GB, $0.13 per MB/s)
• 240GB SSD: 533 MB/s read, 549 MB/s write, $240 per drive ($1.00 per GB, $0.22 per MB/s)
• 120GB SSD: 531 MB/s read, 538 MB/s write, $129 per drive ($1.08 per GB, $0.12 per MB/s)
• 60GB SSD: 519 MB/s read, 523 MB/s write, $84.50 per drive ($1.41 per GB, $0.08 per MB/s)
• 1TB SATA: 158 MB/s read, 137 MB/s write, $86 per drive ($0.09 per GB, $0.29 per MB/s)

Our engineers ran the Bonnie++ benchmark to compare SSDs with 7200RPM SATA and 15K SAS drives. The results show some pretty compelling data that suggests SSDs may be the best option if speed is a requirement.

Consult with your Advanced Clustering Technologies sales rep at sales@advancedclustering.com or technician to find out which drive is best for you.