Changes

|Exceeding 99.99999% uptime per year; individual components failing won't cause performance or capacity issues|99.999% to 99.9999% uptime per year; individual components failing may cripple performance or capacity, but won't affect current tasks|Poorly built ones could run into trouble every few hours under a high burden; unplanned downtime of proper prebuilt servers is around a few minutes to 1 hour per month; individual components failing always break all current tasks|Varies (usually less than 99.9999% per year) depending on SLAs and configuration; each node follows the failure model of regular PC-based servers; nodes failing may cripple performance or capacity, but won't affect current tasks|Not a priority, some supercomputers even run periodically every day; nodes failing may cripple performance or capacity, and may break current tasks