Lynn McGuire said:
"? I feel ethically and morally obligated to let you in on a
dirty little secret I've discovered in the last two years of
full time SSD ownership. Solid state hard drives fail. A lot.
And not just any fail. I'm talking about catastrophic,
oh-my-God-what-just-happened-to-all-my-data instant gigafail.
It's not pretty. "
Lynn
It depends on your usage pattern and the SSD. Failure rate is
a designed feature with SSDs, i.e. the manufacturers know pretty
well how much writing an SSD can take. By designing wear-leveling
and spare capacity, they can design a specific write load
that kills a drive. In the beginning, this process is shaky
though and whole drive series can have worse reliability.
The typical reliability design goal is a 5% failure rate
per year for an average usage pattern. Consumers are willing
to tolerate that. That is a real failure rate, but it is
not "all the time". There are people that think because SSDs
are not suceptible to mechanical damage, they could do without
backup. Thise people will lose their data, no matter what
storage medium it is on, untill some day no money can be saved
by aiming for that 5% and reliability slowly goes up.
That said, I think the coding horror person (which has some
prrry nice things about coding in his blog) has a census of
mostly early models. These, like any new technology, have
increased failure rates, as the manufacturers try to aim
for that 5%/year but make mistakes in the process. It could
also just be a statistical annomaly.
There is one additional thing: SSDs are susceptible to
heat, just like any other electronics and to bad power.
It is possible that the guy with the 8 of 8 dead deives
just killed them by overheating or by voltage-spikes
from a cheap/bad PSU. For heat, rule of thumb is half
the lifetime every 10C for semiconductors and this works
pretty well. I have seen it several times now, one a 22
unit network card sample. As SSDs contain power circutry,
some parts of them run much hotter (step-up regulators for
converting 5V to the write-voltage needed), and lifetime
of 5 years is typically calculated at 40C environmental
temperature. Run them at 60C and you get 1.25 years average
lifetime. Other example: Memory and logic chips have something
like 30 years at 25C (figure from a very old Intel databook).
Run them at 65C and you get around 2 years lifetime.
That means you get the first failured (depending on
sample size) after 1-1.5 years and after 3 years most are
dead. This incidentally was my intital measurement and
prediction for the 22 network cards and what happened
then. Note that high-performance CPUs are different, as
they are more designed as power semiconductors. But chipsets
are not. I have seen several fail from inadequate cooling
in 1-3 years.
There is one other effect at work here: A lot of people
expected SSDs to be much more reliable than HDDs.
They are not in general, see above. This can lead
to disappointments causing overstatement of the problem.
Altogether, I don't believe we are seeing more than
early-adopter problems, and they are always the same.
Also, there are certainly cheap SSDs and better
SSDs, just like allways and it is possible to treat SSDs
well or badly.
Arno
