Disabling High Availability
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To disable High Availability, all leaves in availability group 2 need to be deleted and either removed from the cluster or re-added into availability group 1.
Before You Start
If the cluster is configured with leaf_ set to load_, change it to paired before removing the leaves:
SHOW VARIABLES LIKE '%fanout%';
+--------------------------------------+
| Variable_name | Value |
+--------------------------------------+
| leaf_failover_fanout | load_balanced |
---------------------------------------+
1 row in set (0.00 sec)SET GLOBAL leaf_failover_fanout='paired';
Query OK, 0 rows affected (0.01 sec)Step 1.
Connect to SingleStore on the master aggregator and list the leaves to find the ones in availability group 2.
sdb-admin list-nodes -r leaf
+------------+------------+-------+------+---------------+--------------+---------+----------------+--------------------+
| MemSQL ID | Role | Host | Port | Process State | Connectable? | Version | Recovery State | Availability Group |
+------------+------------+-------+------+---------------+--------------+---------+----------------+--------------------+
| 4DAE7D1F54 | Leaf | node1 | 3310 | Running | True | 6.7.7 | Recovering | 2 |
| 52CA34CD0C | Leaf | node1 | 3311 | Running | True | 6.7.7 | Online | 2 |
| 74BBE83C45 | Leaf | node1 | 3308 | Running | True | 6.7.7 | Online | 1 |
| A6D82670D8 | Leaf | node1 | 3309 | Running | True | 6.7.7 | Online | 1 |
+------------+------------+-------+------+---------------+--------------+---------+----------------+--------------------+Then run sdb-admin remove-leaf on each leaf in availability group 2:
sdb-admin remove-leaf --memsql-id 4DAE7D1F54 -y
sdb-admin remove-leaf --memsql-id 52CA34CD0C -y
Run sdb-admin list-nodes again to verify only the two leaves in availability group 1 are listed.
sdb-admin list-nodes -r leaf
+------------+------+-------+------+---------------+--------------+---------+----------------+--------------------+
| MemSQL ID | Role | Host | Port | Process State | Connectable? | Version | Recovery State | Availability Group |
+------------+------+-------+------+---------------+--------------+---------+----------------+--------------------+
| 74BBE83C45 | Leaf | node1 | 3308 | Running | True | 6.7.7 | Online | 1 |
| A6D82670D8 | Leaf | node1 | 3309 | Running | True | 6.7.7 | Online | 1 |
+------------+------+-------+------+---------------+--------------+---------+----------------+--------------------+Step 2.
On the master aggregator run:
SET @@GLOBAL.redundancy_level = 1;
This updates the current configuration and sets the cluster to run in redundancy-1 operation mode.
In addition, update the SingleStore configuration file on the master aggregator to make sure the change is not lost whenever it is restarted.
sdb-admin list-nodes --role master -q | xargs -I % sdb-admin update-config --memsql-id % --key redundancy_level --value 1 --set-global -y
Step 3.
Optionally, you can re-add the deleted leaves into the availability group 1.
List the nodes in your cluster so you know which ones to add back in:
sdb-admin list-nodes
+------------+------------+-------+------+---------------+--------------+---------+----------------+--------------------+
| MemSQL ID | Role | Host | Port | Process State | Connectable? | Version | Recovery State | Availability Group |
+------------+------------+-------+------+---------------+--------------+---------+----------------+--------------------+
| 43F1B836D3 | Master | node1 | 3306 | Running | True | 6.7.7 | Online | |
| E4921A995C | Aggregator | node1 | 3307 | Running | True | 6.7.7 | Online | |
| 74BBE83C45 | Leaf | node1 | 3308 | Running | True | 6.7.7 | Online | 1 |
| A6D82670D8 | Leaf | node1 | 3309 | Running | True | 6.7.7 | Online | 1 |
| 4DAE7D1F54 | Unknown | node1 | 3310 | Running | True | 6.7.7 | Recovering | |
| 52CA34CD0C | Unknown | node1 | 3311 | Running | True | 6.7.7 | Recovering | |
+------------+------------+-------+------+---------------+--------------+---------+----------------+--------------------+To re-add the leaves into the availability group 1, run the following on the leaf nodes you previous removed:
sdb-admin add-leaf --memsql-id 4DAE7D1F54
sdb-admin add-leaf --memsql-id 52CA34CD0C
Run sdb-admin list-nodes one more time to show the leaves added back into the cluster, but in availability group 1.
sdb-admin list-nodes
+------------+------------+-------+------+---------------+--------------+---------+----------------+--------------------+
| MemSQL ID | Role | Host | Port | Process State | Connectable? | Version | Recovery State | Availability Group |
+------------+------------+-------+------+---------------+--------------+---------+----------------+--------------------+
| 43F1B836D3 | Master | node1 | 3306 | Running | True | 6.7.7 | Online | |
| E4921A995C | Aggregator | node1 | 3307 | Running | True | 6.7.7 | Online | |
| 4DAE7D1F54 | Leaf | node1 | 3310 | Running | True | 6.7.7 | Recovering | 1 |
| 52CA34CD0C | Leaf | node1 | 3311 | Running | True | 6.7.7 | Recovering | 1 |
| 74BBE83C45 | Leaf | node1 | 3308 | Running | True | 6.7.7 | Online | 1 |
| A6D82670D8 | Leaf | node1 | 3309 | Running | True | 6.7.7 | Online | 1 |
+------------+------------+-------+------+---------------+--------------+---------+----------------+--------------------+Next, rebalance the cluster by running REBALANCE ALL DATABASES.
REBALANCE ALL DATABASES;
The cluster will now contain orphan partitions - in fact, the old replica partitions.SHOW CLUSTER STATUS, and deleted by running on the master aggregator:
CLEAR ORPHAN DATABASES;
Last modified: April 29, 2024