Re: New server setup
От | Mark Kirkwood |
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Тема | Re: New server setup |
Дата | |
Msg-id | 51414409.6090505@catalyst.net.nz обсуждение исходный текст |
Ответ на | Re: New server setup (David Boreham <david_list@boreham.org>) |
Ответы |
Re: New server setup
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Список | pgsql-performance |
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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