Hosting again

Simon Wilcox essuu at
Mon Oct 29 16:44:23 GMT 2007

Alistair McGlinchy wrote:
> You've just hit one of my favourite niggles.  Why do you want 
> redundant networks and sites AND redundant memory, processors and 
> power supplies within a site? [*]  This a waste of money, you end up 
> spending 4 times the money for only N/2 resilience. If you want extra
>  resilience, add another site or buy components with better MTBF.

> [*] I removed the disks issue as RAID5 provides cost effective
> resilience for a high MTBF component and with massive hassle
> reduction when they fail.

Agreed for memory and processors but redundant PSUs and fans are quite
useful as you don't need to stop the box to replace the faulty part.

These being mechanical parts they're much more likely to fail than
memory or processors and I've yet to see a system that could
successfully recover from a faulty CPU. Hot swap CPU seems like a
marketing gimmick than something actually useful. At least at the
commodity server end of the market. In a n-way mainframe, it's probably
a very good idea :-)


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