On 14/03/13 09:16, David Boreham wrote:
On 3/13/2013 1:23 PM, Steve Crawford wrote:
What concerns me more than wear is this:
InfoWorld Article:
http://www.infoworld.com/t/solid-state-drives/test-your-ssds-or-risk-massive-data-loss-researchers-warn-213715
Referenced research paper:
https://www.usenix.org/conference/fast13/understanding-robustness-ssds-under-power-fault
Kind of messes with the "D" in ACID.
It is somewhat surprising to discover that many SSD products are not
durable under sudden power loss (what where they thinking!?, and ...why
doesn't anyone care??).
However, there is a set of SSD types known to be designed to address
power loss events that have been tested by contributors to this list.
Use only those devices and you won't see this problem. SSDs do have a
wear-out mechanism but wear can be monitored and devices replaced in
advance of failure. In practice longevity is such that most machines
will be in the dumpster long before the SSD wears out. We've had
machines running with several hundred wps constantly for 18 months using
Intel 710 drives and the wear level SMART value is still zero.
In addition, like any electronics module (CPU, memory, NIC), an SSD can
fail so you do need to arrange for valuable data to be replicated.
As with old school disk drives, firmware bugs are a concern so you might
want to consider what would happen if all the drives of a particular
type all decided to quit working at the same second in time (I've only
seen this happen myself with magnetic drives, but in theory it could
happen with SSD).
Just going through this now with a vendor. They initially assured us
that the drives had "end to end protection" so we did not need to worry.
I had to post stripdown pictures from Intel's s3700, showing obvious
capacitors attached to the board before I was taken seriously and
actually meaningful specifications were revealed. So now I'm demanding
to know:
- chipset (and version)
- original manufacturer (for re-badged ones)
- power off protection *explicitly* mentioned
- show me the circuit board (and where are the capacitors)
Seems like you gotta push 'em!
Cheers
Mark
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