Create a replica

Limitations

If a tenant already has replicas in all zones of the cluster, you cannot create more replicas.

Background

SQL syntax for creating a resource unit

CREATE RESOURCE UNIT unitname
MAX_CPU [=] cpunum,
[MIN_CPU [=] cpunum,]
MEMORY_SIZE [=] memsize,
[MAX_IOPS [=] iopsnum, MIN_IOPS [=] iopsnum,IOPS_WEIGHT [=]iopsweight,]
[LOG_DISK_SIZE [=] logdisksize];

SQL syntax for creating a resource pool

CREATE RESOURCE POOL poolname
UNIT [=] unitname,
UNIT_NUM [=] unitnum,
ZONE_LIST [=] ('zone' [, 'zone' ...]);

SQL syntax for allocating a resource pool to a tenant

ALTER TENANT tenant_name
RESOURCE_POOL_LIST [=](poolname [, poolname...]);

SQL syntax for adding a replica to a tenant

ALTER TENANT tenant_name LOCALITY [=] 'locality_description';

Procedure

Assume that the tenant1 tenant has only one replica, hosted in zone1, and that you need to create a replica in zone2 for the tenant. Modify the locality of tenant1 to increase the number of replicas.

1. Log on to the sys tenant as the root user.

2. Create a resource unit.

   obclient> CREATE RESOURCE UNIT unit1 MAX_CPU 4, MIN_CPU 4, MEMORY_SIZE '5G', MAX_IOPS 1024, MIN_IOPS 1024, IOPS_WEIGHT 0, LOG_DISK_SIZE '2G';
   

3. Create a resource pool for zone 2.

   obclient> CREATE RESOURCE POOL pool2 UNIT='unit1', UNIT_NUM=1, ZONE_LIST=('zone2');
   

4. Allocate the resource pool of zone2 to tenant1.

   obclient> ALTER TENANT tenant1 resource_pool_list=('pool1','pool2');
   

5. Add a full-featured replica of zone2 to tenant1.

   obclient> ALTER TENANT tenant1 locality='F@zone1,F@zone2';