fault tolerant web servers on freebsd

[jfarmer at goldsword.com]

Quoting Maciej Jan Broniarz <gausus at gausus.net>:
> W dniu 10-04-05 22:08, Tonix (Antonio Nati) pisze:
>> Maciej Jan Broniarz ha scritto:
>>> W dniu 10-04-05 17:45, Mike Jakubik pisze:
>>
>> Just to use exact words, fault toulerancy is not possible with any
>> FreeBSD/Linux O.S.
>> F.T. means outage can occur in every moment, but all current operation
>> will be always completed by other equipments; so there will not be
>> interrupted/lost operations.
>
> Hmm. Thanks for the tip. Which *NIX os can be used to build an FT
> solution then? Solaris? AIX? HP-UX?

You're asking a question that has not easy or compete answer.  Fault  
tolerant at what level?  Do you want to guarantee that _every_ DB  
operation competes?  What about random file reads or writes? Do you  
want to guarantee that two identical operations with the same data  
will produce the same result? (That's _not_ the same as the previous  
questions...)

So first you have to define your workload, then define what errors you  
must avoid or allow, and then define how to deal with failures,  
errors, etc.

Then you can start talking about High Availability vs. level of Fault  
tolerance, vs. ....

John

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J. T. Farmer <jfarmer at goldsword.com>    <jfarmer at orfencer.org>
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