Uptime

When it comes to system availability, whether for “ cloud computing “ or on a “ platform “ , people frequently hear about ” 9’s ” of uptime.  Many service level agreements (SLAs) specify at least 99.9 % availability (3 9’s  – or –  < 9 hours of downtime / year), or, 99.99 % (4 9’s – or –  < 1 hour of downtime / year).  In conjunction with this, to further define system performance, the SLA Availability Metrics agreed on need to be from the End User perspective and apply from the time the application initially goes live.