[Asterisk-Users] Hardware to build an Enterprise AsteriskUniversal Gateway

[Steven Critchfield]

On Fri, 2004-01-09 at 21:36, Steve Underwood wrote:
> WipeOut wrote:
> 
> > Granted five 9's is never easy but in a cluster of 10+ servers the 
> > system should survive just about anything short of an act of God..
> 
> You do realise that is a real dumb statement, don't you? :-)
> 
> A cluster of 10 machines, each on a different site. Guarantees from the 
> power company - checked personally to see that aren't cheating - that 
> you have genuinely independant feeds to these sites. Large UPSs, with 
> diesel generator backups. Multiple diverse telecoms links between the 
> sites, personally checked multiple times to see there is genuine 
> diversity (Its a waste of time asking a telco for guarantees of this 
> kind, as they lie by habit). This *might* start to approach 5 9's. Just 
> having 10 servers means *very* little.

Maybe the fact that the main clusters I have knowledge or in university
settings meant to increase compute power, but cluster tends to have the
connotation of being in one location. In the case of a single location,
the extra machines do mean higher odds of loosing parts due to average
time between failure. A friend of mine made a comment about one of the
top 500 super computer clusters maintenance having to have a box of
memory, and drives. It was mentioned that they lost a certain number of
memory modules a day. That freaked me out as the only times I had
experienced memory failure was due to miss handling not normal course of
computer operation. 

The setup you mention above isn't what I would normally associate with
clustering. It also is unlikely to make a difference for a single office
location keeping their system available.
-- 
Steven Critchfield <critch at basesys.com>