Measuring availability Based on 24x7 operations, Planned and unplanned outages. Percent of availability* 99%99.9%99.99%99.999%99.9999%99.99999% Outage minutes/ year ~5,000~500~50~5~.5~.05 Outage to users 3.65 days8.8 hrs.~50 min.5 min.30 sec.3 sec.
HP NonStop availability and location based services
1213 February 2014 Increasing the availability – toward Seven, Eight & Nine 9s
The New NonStop Advanced Architecture DMR: Dual Modular Redundancy TMR: Triple Modular Redundancy (HW Availability: seven 9s) Loose Synchronization (lock-step) Each server runs on its own clock. Each can perform soft error corrections without causing a miscompare. Self-checked, shared-nothing, transparent take- over Fault Masking – HW Processor failures are masked and are not visible to all SW except for lowest level of OS. E.G. an uncorrectable memory error doesnt stop the logical processor, it simply stops one processor element that makes up the logical processor. Memory has one of the highest rates of failure. NSAA masks all memory failures. Repairs dont result in SW disruption either. Fault-tolerant parallel database Application server transaction processing monitors 1313 February 2014
1413 February 2014 Dual to Triple-Mode Redundancy Dual-Mode Redundancy = Five 9s Availability Triple-Mode Redundancy = Seven 9s Availability