On 13/01/2012 07:17 PM, Warp wrote:

>    One would think that if the server is mission-critical, it would have
> redundant hardware. In other words, if for example a memory module dies,
> the only consequence is that the amount of available RAM decreases and
> a big-ass notification is logged somewhere, but otherwise the service
> continues as usual.
>
>    Of course this requires specialized server hardware, as well as
> software support. (I don't even know if Windows supports this. I'm
> assuming NT and its spawns ought to, but I have never heard either way.)

For a time we had a HP ProLiant server with a memory "RAID" feature. 
(This is on top of all the memory being ECC RAM.) It's transparent to 
the OS.

For example, I might fit two 4GB RAM modules in a mirror configuration. 
The OS sees 4GB installed. If the ECC on one of them starts reporting 
uncorrectable errors, the system board will transparently fetch data 
from the other RAM module, as if nothing ever happened. In addition, an 
LED lights up on the front of the chassis, showing you exactly where on 
the motherboard the failed RAM module is, so you can replace it. (I'm 
unsure whether it was hot-swappable...)

Additionally, there were lights for EVERY INDIVIDUAL FAN (all 15 of 
them), both CPU sockets (so if one CPU dies, the server continues 
running - although I guess the OS is going to notice that one), and both 
of the redundant PSUs.

>    And also I'm assuming this is not cheap, so management do not want.


as you might imagine. (I mean, sure, that's more money than *I* will 
ever own. But for a professional business enterprise, it's potentially 
not a lot of money.)

-- 
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*

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