Re: SSDs with Postgresql?

On 4/28/2011 8:20 AM, Scott Ribe wrote:
>> I don't think you can simply say that I am writing so many Gb WAL files, therefore according to the vendor's spec
> Also, I fully expect the vendors lie about erase cycles as baldly as they lie about MTBF, so I would divide by a very
healthyskepticism factor. 
>

As a former card-carrying semiconductor company employee, I'm not so
sure about this. I'd expect a healthy guard-band on the erase cycles
spec (so if they say 100K, the devices will actually achieve better than
2X). MTBF otoh is a mythical computed value that everyone takes with a
big pinch of salt, in my experience. I'm not sure it is possible to lie
about MTBF since it's essentially just the result of a calculation based
on the number of contacts, cells, traces, etc and the known failure
mechanisms for those things. Therefore it will be "true", but not
necessarily useful (e.g it does not take account of process defects or
an aging mechanism that were not known at the time of manufacture).