Analyzing Long-Term SSD Failure Rates 149
wintertargeter writes "It looks like Tom's Hardware has posted the first long-term study of SSD failure rates. The chart on the last page is interesting — based on numbers, it seems SSDs aren't more reliable than hard drives. "
Huh? (Score:5, Insightful)
Re:Uh, yes they are (Score:5, Insightful)
Did the poster even look at the chart he linked to?
Did you? Apparently not.
Ignore the dashed lines-- those curves are not data, they are "projection." The chart has no data on SSD failures late in the lifetime. So, when you say "...SSD failures only exceed HD failures very early on in their lifetimes," that is equivalent to saying "SSD failures only exceed HD failures in the region of the graph for which there is data."
Re:Who said they were? (Score:4, Insightful)
Re:Uh, yes they are (Score:4, Insightful)
Worst. Ever. (Score:5, Insightful)
Let me summarize:
A) Chart is worthless. I have never see a more ambiguous meaningless chart in my life. They might as well not bother to label things.
B) Lets do a reliability study on SSD's that they don't have any long term data on past 2 years, yet compare it to HDD that typically at least have a 3 year warranty. By that I only mean, I'll go out on a limb and guess that the average failure rate of HDD is > 3 years, if only for economic self preservation.
C) Results in either case depend highly on specific device model and configuration.
Re:Uh, yes they are (Score:2, Insightful)
You do know that HDDs also require wear leveling right? (Well, not really, but defective blocks were pretty much part of life when HDDs were in the 10-100MB size.)
So yes, both SSDs and HDDs are likeyly to wear out after time. What wear leveling does is that it makes sure that the entire disk is pretty much worn out when you start encountering bad blocks.
With SSDs there is however one slight improvement. Since flash memory have been used for so long without wear leveling and in applications were it's damn important to get a good estimate of the the product life (Advanced fire alarms, mars probes and such.) it is actually possible to get good information on when a SSD is likely to fail.
I assume that HDD manufacturers have at least some clue of how many writes their disks will take before it is worn out (Otherwise they will have to alocate unused blocks for the wear leveling on a hunch.) but good luck getting that information from them.
So yes, both SSDs and HDDs are likely to fail sometime. The big difference is that if you are designing a system where it actually matters you can actually select an SSD with the correct specification. If it really matters you are probably going to get SLC anyway. If you don't want to pay for it it is likely that you don't need reliability.