[LINK] Green web servers with netbook components

grove at zeta.org.au grove at zeta.org.au
Thu May 21 09:20:32 AEST 2009

On Wed, 20 May 2009, Tom Worthington wrote:

> At 09:57 PM 19/05/2009, Bernard Robertson-Dunn wrote:
>> ... My experience of servers in data centres is that reliability and
>> availability are very important ...
> Reliability and availability can be provided by redundant servers,
> rather than servers with redundant components. That is you provide
> more than one server, so that if any of the components fail (power
> supply, disk, network connection or CPU) the other server takes over.
> This is the approach Google takes
> <http://www.tomw.net.au/blog/2009/04/google-battery-backed-shipping.html>.
> With this approach the design of the individual servers is much
> simpler, at the cost of increased complexity in the software. This
> also provides for the components to be geographically separated for
> another level of redundancy.

I architected a system like this, that has been going since 2005. 
We call it "horizontal scaling".   Each webserver is a Sun B100 blade 
in a shelf with 3 such shelves in different geographical locations, 
served behind a content switch.

Each blade contains:

1x36Gb disk 
2Gb RAM 
1x 1Ghz CPU

Each blade runs a copy of Solaris in a rather lightweight mode.  Just the 
OS, no apps.

The web farm is mounted via NAS to a mountpoint that is shared amongst
all the blades.  Every blade runs the same copy of the software/web 
individually.  we use apache vhosts to serve the farmed sites up. 
Logging is done to local disk and processed via a merge script on a logserver.

I keep asking for "splunk" so I can get rid of my crappy scripts, but 
the managers don't "get it".

The setup is extremely robust.   The NAS is replicated so we can lose 
a whole 2 datacentres and still serve the farm.

I am a big fan of horizontal scaling as a result.   It will scale to
  quite a huge setup.   With reliance on a blade, rather than a 
virtual zone, I can get a lot more processing power and page serves 
out of each one.


> Tom Worthington FACS HLM tom.worthington at tomw.net.au Ph: 0419 496150
> Director, Tomw Communications Pty Ltd            ABN: 17 088 714 309
> PO Box 13, Belconnen ACT 2617                      http://www.tomw.net.au/
> Adjunct Senior Lecturer, Australian National University
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Rachel Polanskis                 Kingswood, Greater Western Sydney, Australia
grove at zeta.org.au                http://www.zeta.org.au/~grove/grove.html
We are buried beneath the weight of information, which is being confused with
knowledge; quantity is being confused with abundance and wealth with happiness.
- Tom Waits

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