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| SMSEagle NXS-9700
| User’s Manual
Failover (HA-cluster) feature
"High-availability clusters (also known as HA clusters or fail over clusters) are groups of computers (...) that can be
reliably utilized with a minimum of down-time. They operate by using high availability software to harness
redundant computers in groups or clusters that provide continued service when system components fail. Without
clustering, if a server running a particular application crashes, the application will be unavailable until the crashed
server is fixed. HA clustering remedies this situation by detecting hardware/software faults, and immediately
restarting the application on another system or whole node without requiring administrative intervention, a process
known as failover."
(source: Wikipedia)
SMSEagle NXS-family devices have their own failover mechanism based on HA-cluster. This feature allows
you to assure high availability of SMSEagle devices in critical environments. To enable failover (HA-cluster)
you need 2 devices ('aka' nodes). The failover feature monitors devices working in the cluster, and detects
faults with the following services:
1.
Apache2 WWW server
2.
PostgreSQL database
3.
SNMP agent
4.
Modem software (Gammu-SMSD daemon)
5.
Accessibility (response to ping) of whole node.
Every node in a cluster can have one of three states:
•
Master:
main healthy node in a cluster, by default accessible through Virtual IP
•
Backup:
second healthy node in a cluster, ready and waiting for replacing Master when needed
•
Fault:
node with detected service fault
Содержание NXS-9700-3G
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