[CentOS] Intel NUC? Any experience

John R Pierce pierce at hogranch.com
Fri Jan 9 00:25:00 UTC 2015


On 1/8/2015 3:40 PM, david wrote:
> Thanks for your comments.  In the particular application, I used the 
> word "server" only in the sense that GUI is only rarely used, and CPU 
> speed isn't an issue.  The data the server holds has other "primary" 
> copies elsewhere, so if some corruption or damage occurs, it can be 
> restored within acceptable time.  Thus, I am not interested in ECC 
> memory or RAID for this situation, although I do appreciate the need 
> for servers with mission-critical data.  As a former employee of 
> Tandem Computers, mirroring, backup, check-everything, dual everything 
> is in my blood. 

the problem with non-ECC memory is, you never KNOW when data corruption 
has happened.   Making life more complicated, the statistical rate of 
these soft bit errors varies widely from machine to machine as a 
significant cause is background radioactivity, and other components of 
the system such as the chassis materials can contribute to this.   I've 
seen numbers ranging from a few errors per century per gigabyte to a few 
per HOUR per gigabyte.    without ECC, you simply don't know this has 
happened, unless the flipped bit happens to be in some code in a place 
and position where it causes the code to crash, or you happen to notice 
corruption, such as a block decode error while playing a video (which, 
for formats like mpeg/mp2/mp4 can cause video block glitches for several 
seconds until a new I-frame restores the whole picture).

I really wish the PC industry made ECC the norm even for desktop 
workstations.  it only adds 12% to the memory cost (9 bits instead of 8 
bits per byte, or 72 instead of 64 per word), and the memory cost is 
typically about a 10th of the total system price, such that the cost of 
ECC would only be 1% or so....    but since ECC is 'special server only' 
stuff, it costs a premium far above and beyond that 12%.



-- 
john r pierce                                      37N 122W
somewhere on the middle of the left coast




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