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Hi Rio
Rio schrieb:
> it is FAR cheaper to run a few hosts running virtuals than to run real
> hardware. the more hardware you run the more you increase your chances of a
> hardware failure. although possibly measurable, we have absolutely no
> noticable difference in efficiency of services between virtuals and real
> hardware.
>
You quite missed the point. Cost-efficiency and HA never match nor be a
difference - they are distinct :-)
Joseph critiziced that virtualisation alone is not the answer to HA -
and he is right.
The combination of virtualisation _AND_ LVS may be a answer to future
quests for HA .
We and surely several others run virtualized server-clusters with many
virtual servers embedded into one big box.
As Joseph states a critical faillure of this box will costs us as much
cutomers as we have v-servers on this box :-)
_BUT_ we have a second big box which is the realtime mirror of the first
one by the virtue of DRBD.
So if big box one fails ...
to cite Joseph:
> If you need failover (do virtual servers fail?)
> why not just 5 machines (enough that you'll only loose 20%
> on failure)?
the second box takes over by the virtue of heartbeat and reboots the
mirrored virtual instances.
[This is not truly our aproach. We use virtual realservers spread across
some big boxes via ipvs wich share
some cluster-filespace. This is truely HA]
Imagine the future in 2-5 years. A typical server will have 8 to 16
CPU-cores with 2 MHz.
Without virtualisation you will ony enlarge the CO2 footprint of you
datacenter but you will not be
cost-efficient nor you will be more HA than with distinct boxes.
I post this not to put oil in the fire, but to promote a fruitful
discussion on the benefits of combining
virtualisation with LVS.
Best regards,
Volker
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Dr. Volker Jaenisch http://www.inqbus.de
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