Python and the need for speed

Christian Gollwitzer auriocus at gmx.de
Fri Apr 14 02:29:22 EDT 2017


Am 13.04.17 um 15:20 schrieb Marko Rauhamaa:
>
> Not sure if this is still valid:
>
>    Still today Flash RAM cells built in SSDs have a limited lifespan.
>    Every write (not read) cycle or better every erasure wears a memory
>    cell and at some time it will stop working.
>
>    <URL: https://askubuntu.com/questions/652337/why-no-swap-partition
>    s-on-ssd-drives>
>

It is true, in general, but the lifetime has gotten MUCH better due to 
overprovisioning and intelligent wear leveling. The German computer 
magazine c't has tested a few current SSDs by filling them over and over 
again with random numbers 24/7 until they failed [1]. For these drives 
with a capacity of 256GB, the manufacturers guaranteed ~70 TB written to 
them, for Samsung 850 Pro and SanDisk Extreme 150TB were guaranteed. 
Most drives withstood much more data, the best one being the Samsung 850 
Pro, which did not fail until they ended the test after writing 4600 TB 
in half a year. The others failed at ~1000 TB.

So, unless you really plan to fully use them as a cache for number 
crunching TB sized data blocks, they will practically not fail.
The failure mode, however, was very abrupt - unlike from a hard drive, 
where you can sometimes recover portions of the data, the full drive is 
completely dead from one point on.


	Christian

[1] 
https://www.heise.de/newsticker/meldung/SSDs-im-Stresstest-mit-ueberraschenden-Ergebnissen-3580824.html




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