Total Cost of Ownership (TCO) implications

---

The cost of SSDs for a program/project extends beyond the initial purchase of the SSDs. The application, the work load (how data is written to the SSD), and the operating environment, the longevity of a defense program all have a tremendous impact on the lifespan and cost of SSDs.

Too often we see customers attracted to a low initial purchase price, with obvious good intentions, only to be forced to spend significantly more time and money over the life of a program in troubleshooting, SSD replacements, and/or data loss and corruption. Many vendors are happy to sell a less expensive SSDs with low endurance to get written into a program, knowing the end-customer will be forced  to keep coming back to purchase a replacement SSDs every year. 

When analyzing Total Cost of Ownership of SSDs for your program, consider: 

• SSD Endurance – how long each drive will last (read our SSD Endurance blog post)
• Operational Environment - Component selection and build quality make a huge difference in high/low temperatures, high shock, high vibration environments
• Program Longevity - How often you will have to replace SSDs for the life of the program, and how much it costs to replace SSD
• Risk/cost of application failure, data corruption and/or data loss

Understanding how and where you deploy the SSD will save you money in the long run. 

Operating environment (mostly temperature) and write-intensity will determine the strain on the SSD, and help determine the lifespan of an SSD. Room temperature and mostly reading are benign for SSDs, little wear and tear. On the other hand, a write-intensive application such as a data recorder, especially at higher temperatures, will quickly wear SSDs. 

All NAND Flash has a limited number of Program/Erase (P/E) cycles.

• Upgrading from QLC to MLC NAND is a 3.75x improvement in Write Endurance. QLC = 800 P/E cycles | MLC’s = 3000 P/E cycles

• SLC NAND offers 10x – 30x the write endurance of MLC (SLC offers between 30,000 P/E cycles to 100,000 P/E cycles, depending on SLC grade)!

More info here. 

Operating in high shock and high vibration environments takes a toll on all the components inside the SSD. The cases, components, and connectors all have their own lifespan and MTBF, and therefore can only handle so much. Building a SSD to your operating environment is a game changer.

For example, a standard SATA connector is only rated to 6gRMS, and ~125-200 insertion/removal cycles before the metal starts to wear off connectors. Using a ruggedized SATA connector allows you to increase that up to 30gRMS and 20,000 insertion/removal cycles in the same footprint. The same goes for all the other components inside the SSD. Some drives are built cheaply to ensure low cost / gigabyte. Others are built to withstand whatever situation you deploy them in, allowing you to replace the SSDs considerably less often.

Once a drive is starting to fail, or has failed, a number of costs are associated with the replacement. 

• Cost of replacement SSD - assuming it is still available and not EOL
• Product validation / qualification / re-qualification / re-validation - if previous SSD no longer available, more expensive, or EOL
• Labor and time of actual replacement - Where in vehicle is SSD located? How easy is it to maintain spares and/or ship replacement

Hopefully the drive does not fail out on a mission. If it does, what is the cost of the data corruption/failure? Depends on the application. If the SSD is used in a navigation system, or a data recorder, etc. How easy is it to get to the system? SSD inside an easy to access server, or inside the wing of an aircraft or in a submarine that's supposed to stay underwater for a few months? How easy is it to get a drive that is validated for the system? If drive has gone EOL, how quickly can we validate a replacement. Is there any technology risk that replacement drive will not work the same way?  

Hand-in-hand with replacement costs, cost of data loss varies. Data recovery is generally expensive, if at all possible. Downtime has a different cost based on application. Used in a tank or armored vehicle, navigation and control systems are paramount. Our warfighters cannot rely on gear that suffers performance issues because temperatures are too cold or too hot. 

When the mission requires an airborne data-recorder, how much does it cost to re-fly the mission because the data got corrupted? Heavy workloads on low endurance drives increase application disruptions and require more frequent drive replacements.  How much does system repair/redesign/revalidation cost?

Consumer grade SSD prices have been dropping thanks to TLC and QLC NAND, and being able to fit more bits per cell. In controlled environments, this Flash is great for high capacity in a smaller size, as long as there is not a need for high write endurance.

These technologies are not suitable for applications with 24/7 write requirement. In addition, if you test them out in Military operating temperatures, you'll notice the performance gets significantly throttled at warmer temperatures, well below required operating temps. For these applications, MLC and SLC is recommended for longer SSD lifespan (and better performance)

MEMKOR has an extremely stringent component screening and selection process. We only use high-end components and strong design margins to ensure you can install MEMKOR SSDs between the wheels of a jet, on a chopper, in a submarine, a tank, etc. Our customers deploy MEMKOR SSDs when data is critical.