You must define sqlhosts network-connectivity
information for connection management of high-availability replication
systems.
About this task
To use a file other than $ONEDB_HOME/etc/sqlhosts on
a specific host, set the host's ONEDB_ SQLHOSTS environment
variable to the alternative file.
For this example, you are
setting up Enterprise Replication between the primary servers of three
high-availability clusters.
Cluster 1:
- server_1 (primary)
- server_2 (SD secondary)
- server_3 (HDR secondary)
- server_4 (RS secondary)
Cluster 2:
- server_5 (primary)
- server_6 (SD secondary)
- server_7 (HDR secondary)
- server_8 (RS secondary)
Cluster 3:
- server_9 (primary)
- server_10 (SD secondary)
- server_11 (HDR secondary)
- server_12 (RS secondary)
Procedure
- On the host of each Connection Manager and database server,
create sqlhosts file entries for each server.
For example:
#dbservername nettype hostname servicename options
server_1 onsoctcp host_1 port_1
server_2 onsoctcp host_1 port_2
server_3 onsoctcp host_2 port_3
server_4 onsoctcp host_3 port_4
server_5 onsoctcp host_4 port_5
server_6 onsoctcp host_4 port_6
server_7 onsoctcp host_5 port_7
server_8 onsoctcp host_6 port_8
server_9 onsoctcp host_7 port_9
server_10 onsoctcp host_7 port_10
server_11 onsoctcp host_8 port_11
server_12 onsoctcp host_9 port_12
- On the host of each Connection Manager and database server,
create a sqlhosts file group entry for each replication-server
entry and each cluster. Add group options to each database server
entry. Use the
i=unique_number
group-entry
option to assign an identifier to the group for Enterprise Replication.
Use the c=1
group-entry option for cluster groups,
so that connection-attempt starting points in the list of group members
is random. Use the e=last_member
group-entry
option so that the entire sqlhosts is not scanned
for group members.For example:
#dbservername nettype hostname servicename options
cluster_1 group - - i=1,c=1,e=server_4
server_1 onsoctcp host_1 port_1 g=cluster_1
server_2 onsoctcp host_1 port_2 g=cluster_1
server_3 onsoctcp host_2 port_3 g=cluster_1
server_4 onsoctcp host_3 port_4 g=cluster_1
cluster_2 group - - i=2,c=1,e=server_8
server_5 onsoctcp host_4 port_5 g=cluster_2
server_6 onsoctcp host_4 port_6 g=cluster_2
server_7 onsoctcp host_5 port_7 g=cluster_2
server_8 onsoctcp host_6 port_8 g=cluster_2
cluster_3 group - - i=3,c=1,e=server_12
server_9 onsoctcp host_7 port_9 g=cluster_3
server_10 onsoctcp host_7 port_10 g=cluster_3
server_11 onsoctcp host_8 port_11 g=cluster_3
server_12 onsoctcp host_9 port_12 g=cluster_3
- On the host of each client application, create an sqlhosts file
entry for each service-level agreement (SLA) in each Connection Manager
configuration file.
The first Connection Manager's
configuration file has the following entries:
NAME connection_manager_1
REPLSET my_replset
{
ONEDB_SERVER cluster_1,cluster_2,cluster_3
SLA sla_1 DBSERVERS=ANY
}
CLUSTER my_cluster_1
{
ONEDB_SERVER cluster_1
FOC ORDER=ENABLED \
PRIORITY=1
}
CLUSTER my_cluster_2
{
ONEDB_SERVER cluster_2
FOC ORDER=ENABLED \
PRIORITY=1
}
CLUSTER my_cluster_3
{
ONEDB_SERVER cluster_3
FOC ORDER=ENABLED \
PRIORITY=1
}
The second Connection Manager's configuration file
has the following entries:
NAME connection_manager_2
REPLSET my_replset
{
ONEDB_SERVER cluster_1,cluster_2,cluster_3
SLA sla_2 DBSERVERS=ANY
}
CLUSTER my_cluster_1
{
ONEDB_SERVER cluster_1
FOC ORDER=ENABLED \
PRIORITY=2
}
CLUSTER my_cluster_2
{
ONEDB_SERVER cluster_2
FOC ORDER=ENABLED \
PRIORITY=2
}
CLUSTER my_cluster_3
{
ONEDB_SERVER cluster_3
FOC ORDER=ENABLED \
PRIORITY=2
}
Add the following entries to each client application's
host
sqlhosts file:
#dbservername nettype hostname servicename options
sla_1 onsoctcp cm_host_1 cm_port_1
sla_2 onsoctcp cm_host_2 cm_port_2
- On the host of each client application, create sqlhosts file
group entries for each group of SLA entries, and add group options
to the SLA entries. Use the
c=1
group-entry option,
so that connection-attempt starting points in the list of group members
is random. Use the e=last_member
group-entry
option so that the entire sqlhosts is not scanned
for group members.For example:
#dbservername nettype hostname servicename options
g_sla onsoctcp - - c=1,e=sla_2
sla_1 onsoctcp cm_host_1 cm_port_1 g=g_sla
sla_2 onsoctcp cm_host_2 cm_port_2 g=g_sla
Results
Client connection requests to @g_sla are directed to
one of the Connection Managers. If connection_manager_1 receives
the request, it uses sla_1 to provide the client application
with connection information for the primary server. If connection_manager_2 receives
the request, it uses sla_2 to provide the client application
with connection information for a replication server.