BackBlaze Model Significantly Overstates Cost of LTO Solution

We got by email this analysis from Brad Johns, president, Brad Johns Consulting LLC, following the publication of this article: LTO Vs. Cloud Storage:

Correcting the Backblaze Cloud Storage vs. LTO Cost Calculator

As an independent storage industry analyst and consultant, I have collaborated with clients to develop storage TCO models and read with interest the LTO-8 versus Backblaze Storage Costs article and associated spreadsheet, that appeared in StorageNewsletter on August 17.

Tape media has improved since the 1990s with current formulations of tape having a life expectancy of 30 years or more. However, the Backblaze model assumes that all tapes are replaced at the end of each year well before normal life expectancy. Also, LTO-8 tape media prices have dropped since 2018 and the default LTO-8 price in the calculator remains at the 2018 price of $150/cartridge. Current market prices are in the mid $50 range. Using the default 50TB example, eliminating the annual re-buy and lowering the initial price reduces the cost of tape media by $20,646 compared to the Backblaze calculator.

Another challenging aspect of developing storage TCO is estimating operational labor costs. The Backblaze TCO model allocates 2.5 hours of labor per LTO-8 autoloader per week and scales this estimate linearly based on the number of tape autoloaders. The simple allocation of 2.5 hours per tape autoloader significantly overestimates the labor costs associated with tape storage. Consider that a 50TB full backup requires only 3 LTO-8 tapes with 2:1 compression. Making an adjustment to allocate a total of 2.5 hours total for tape labor and estimate cloud storage management of half this amount the cost of labor for tape falls $33,827. With these adjustments, 5-year cloud costs remain the same at $68,813 while the tape TCO drops to $65,401, actually costing less than the Backblaze cloud back-up solution.

In summary, the cost for the use of tape is consistently overestimated at almost any capacity by the Backblaze calculator. I can appreciate the difficulty in developing a storage TCO model. However, most organizations will find including tape storage in their backup environment to be a very cost-effective and reliable technology for their data protection. This is especially relevant today where cost-effective offline and offsite tape can provide an air gap hedge against ransomware infection.