nStor NexStor 4200F Series, User Manual

Page: 51 / 174

Chapter 2 - Topologies and Operating Modes
How Available are Clusters?
39
How Available are Clusters?
This table outlines the maximum availability per downtime in the different
architectures:
Application of Availability
The NexStor 4200F Series Storage System implementation of availability within its
supported topologies are as follows:
Architecture Maximum Availability Downtime per Failure Downtime per Year
(in minutes)
Continuous Processing 100.00% None 0
Fault-Tolerant 99.9999% Cycles 0.5 - 5
Clusters 99.9 - 99.999% Seconds to
minutes 5 - 500
High Availability 99.9% Minutes 500 - 10,000 (disk
mirroring)
Stand Alone System 99.5% Hours 2,600 - 10, 000
(without disk
mirroring)
Architecture Corresponding Topology
Continuous Processing Not Available
Fault-Tolerant Duplex Dual-Active
Cluster Duplex Dual-Active
High Availability Duplex Dual-Active
Stand Alone System Simplex
4200F.book Page 39 Thursday, January 23, 2003 2:47 PM