[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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