From: ldo@nz.invalid   
      
   On Tue, 11 Nov 2025 18:56:53 -0500, Arne Vajhøj wrote:   
      
   > HA is about whether the system can continue to serve users in case part   
   > of a box or an entire box fail - 24x7 vs 16x5 is about architecture.   
      
   High availability is measured in “nines” -- e.g. five nines, six nines ...   
   even seven nines.   
      
   How do big enterprises (like Google) achieve that? By not using   
   mainframes. They set up data centres full of off-the-shelf PC hardware --   
   one article I remember from over a decade ago said that Google, at that   
   time, had 460,000 servers.   
      
   All the hardware is obtained as cheaply as possible, except one component:   
   the power supply. They buy quality for that, for power-efficiency reasons.   
   As for the rest, it doesn’t matter if a box falls over every minute, or a   
   hard drive crashes every few minutes; they have higher-level redundancy   
   and recovery procedures that can routinely recover from all those   
   failures, without the users ever noticing.   
      
   No mainframe can match that.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)