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Difference between revisions of "Trove-Replication-And-Clustering-API-Single"

m (→‎MongoDB)
(→‎MongoDB)
Line 540: Line 540:
 
== MongoDB ==
 
== MongoDB ==
 
<br>
 
<br>
−
==== 3 Member Replica-Set ====
+
==== Create Replica-Set ====
 
<br>
 
<br>
 
<br>
 
<br>
Line 581: Line 581:
 
<br>
 
<br>
 
Notes:
 
Notes:
−
* Enforce ''replica_set'' field to be provided for MongoDB, even in the case of a standalone/single instance. See http://www.mongodb.com/blog/post/dont-let-your-standalone-mongodb-server-stand-alone for reasoning.
+
* Enforce 'replica_set' field to be provided for MongoDB, even in the case of a standalone/single instance. See http://www.mongodb.com/blog/post/dont-let-your-standalone-mongodb-server-stand-alone for reasoning.
−
* The lack of a ''join'' field indicates that the intention is to create a new replica-set. If an active replica-set by that name already exists, the request will be failed.
+
* The lack of a 'join' field indicates that the intention is to create a new replica-set. If an active replica-set by that name already exists, the request will be failed.
 +
* 'type' is 'member' vs. 'primary' because in a replica-set, the primary is dynamic and can change in an election.
 
<br>
 
<br>
−
'''Add 2nd Member to Replica-Set'''
+
==== Add Member to Replica-Set ====
 
<br>
 
<br>
 
<br>
 
<br>
Line 626: Line 627:
 
* Should return warning when number of voting members is even and there is no arbiter
 
* Should return warning when number of voting members is even and there is no arbiter
 
<br>
 
<br>
−
'''Add 3rd Member to Replica-Set'''
+
==== Add Another Member to Replica-Set ====
 
<br>
 
<br>
 
<br>
 
<br>
Line 659: Line 660:
 
</pre>
 
</pre>
 
<br>
 
<br>
−
'''Show Instance'''
+
==== Show Instance ====
 
<br>
 
<br>
 
<br>
 
<br>
Line 685: Line 686:
 
</pre>
 
</pre>
 
<br>
 
<br>
−
'''Show Topology'''
+
==== Show Topology ====
 
<br>
 
<br>
 
<br>
 
<br>
Line 735: Line 736:
 
</pre>
 
</pre>
 
<br>
 
<br>
−
==== Other Examples ====
+
==== Add Aribiter ====
−
<br>
 
−
'''Add an Arbiter'''
 
 
<br>
 
<br>
 
<br>
 
<br>
Line 771: Line 770:
 
</pre>
 
</pre>
 
<br>
 
<br>
−
'''Add a Delayed Member'''
+
==== Add a Delayed Member ====
 
<br>
 
<br>
 
<br>
 
<br>
Line 809: Line 808:
 
<br>
 
<br>
 
Notes:
 
Notes:
−
* type, join, priority, hidden, and slaveDelay are the only fields supported in topology.mongodb. All other configuration values must be set via a Configuration Group. After more consideration, consider supporting 'hostname' and 'votes'.
+
* 'type', 'replica_set', 'join', 'priority', 'hidden', and 'slaveDelay' are the only fields supported in topology.mongodb{}. All other configuration values must be set via a Configuration Group. After more thought, consider supporting 'hostname' and 'votes' as well.
 +
* Why isn't 'priority', 'hidden' and 'slaveDelay' in Configuration Groups you ask? This is explained in "Modifying a Replica-Set" below.
 +
<br>
 +
==== Modifying a Replica-Set ====
 +
<br>
 +
Thus far we've been able to model building a replica-set, adding an arbiter, adding a delayed secondary member, etc. Let's continue with how to modify a replica-set.
 +
<br>
 +
<br>
 +
Example:
 +
 
 +
<pre>
 +
# from http://docs.mongodb.org/manual/tutorial/configure-secondary-only-replica-set-member/#example
 +
cfg = rs.conf()
 +
cfg.members[0].priority = 2
 +
cfg.members[1].priority = 1
 +
cfg.members[2].priority = 0.5
 +
cfg.members[3].priority = 0
 +
rs.reconfig(cfg)
 +
</pre>
 +
 
 +
Executing these priority changes one at a time can have catastrophic results, so it must be done as a transaction (with rs.reconfig() commiting). However, without the ability to address the cluster (i.e. multiple members at once), this becomes impossible. The only backdoor solution would be to guarantee that the MongoDB user(s) presented to the cloud tenant all have the clusterAdmin role, as this would allow them to connect to the primary and execute such transactions themselves via the native client. Obviously however, granting clusterAdmin to every DBaaS user in MongoDB is unacceptable in most deployments, meaning we're stuck, unless:
 +
<br>
 +
<br>
 +
Request:
 +
 
 +
<pre>
 +
PATCH /instances/dfbbd9ca-b5e1-4028-adb7-f78643e17998/topology
 +
 
 +
{
 +
  "instance": {
 +
    ...
 +
    "topology": {
 +
      "members": [
 +
        {
 +
          "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
 +
          "mongodb": {
 +
    "priority": 2
 +
  }
 +
        },
 +
        {
 +
          "id": "061aaf4c-3a57-411e-9df9-2d0f813db859",
 +
          "mongodb": {
 +
    "priority": 1
 +
  },
 +
        {
 +
          "id": "3a72ee87-cf3e-40f1-a1e1-fe8c7263a782",
 +
          "mongodb": {
 +
    "priority": 0.5
 +
  }
 +
        }
 +
      ]
 +
    }
 +
    ...
 +
  }
 +
</pre>
 +
 
 +
Response:
 +
 
 +
<pre>
 +
{
 +
  "instance": {
 +
    ...
 +
    "topology": {
 +
      "members": [
 +
        {
 +
          "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
 +
          "name": "product-a",
 +
          ...
 +
          "mongodb": {
 +
    "type": "member",
 +
    "replica_set": "products"
 +
  }
 +
        },
 +
        {
 +
          "id": "061aaf4c-3a57-411e-9df9-2d0f813db859",
 +
          "name": "product-b",
 +
          ...
 +
          "mongodb": {
 +
    "type": "member",
 +
    "replica_set": "products"
 +
  },
 +
        {
 +
          "id": "3a72ee87-cf3e-40f1-a1e1-fe8c7263a782",
 +
          "name": "product-c",
 +
          ...
 +
          "mongodb": {
 +
    "type": "member",
 +
    "replica_set": "products"
 +
  }
 +
        }
 +
      ]
 +
    }
 +
    ...
 +
  }
 +
}
 +
</pre>
 +
<br>
 +
Notes:
 +
* An HTTP PATCH vs. PUT because the omission of a field or structure should not be an indication to drop/delete it.
 +
* All modified fields in a request will be changed transactionally in a single rs.reconfig().
 +
* It should now be clear why 'priority', 'hidden' and 'slaveDelay' are in topology.mongodb{} vs. a configuration-group: when a configuration-group is changed, an event is immediately triggered to update any attached trove instances. Therefore, if you have a heterogeneous mixture of configuration-groups in a replica-set, there is no way to coordinate a consolidated rs.reconfig().
 +
* TBD on what should be returned in the mongodb{} on a GET /instance/:id and GET /instance/:id/topology. It's a question of whether we should persist anything beyond the 'type' and 'replica_set'. If say the 'priority' is stored, you introduce the possibility of drift from the truth, but can easily return it on a GET; if it's not stored, do we prompt MongoDB for the truth on a GET, or is that too computationally expensive?
 
<br>
 
<br>
 
==== MongoDB TokuMX ====
 
==== MongoDB TokuMX ====
  
 
* TokuMUX will require a new datastore-version and *possibly* a new manager class (same reasoning as why Tungsten/Galera will have their own datastore-version for MySQL)
 
* TokuMUX will require a new datastore-version and *possibly* a new manager class (same reasoning as why Tungsten/Galera will have their own datastore-version for MySQL)

Revision as of 22:48, 28 February 2014

MySQL


MySQL Master/Slave


For Master/Slave, the server_id must differ, and optionally the slave can specify whether it is read_only or not to avoid accidental writes.

Create Configuration-Group for Master

Request: 

POST /configurations
{
  "configuration": {
    "name": "config-a",
    "datastore": {
      "type": "mysql",
      "version": "mysql-5.5"
    },
    "values": {
      "server_id": 1
    }
  }
}

Response: 

{
  "configuration": {
    "id": "b9c8a3f8-7ace-4aea-9908-7b555586d7b6",
    "name": "config-a",
    "description": null,
    "datastore_version_id": "c5ad9638-b7a1-464b-8cef-721d8c29dbf9",
    "values": {
      "server_id": 1
    }
  }
}


Create Configuration-Group for Slave

Request: 

POST /configurations
{
  "configuration": {
    "name": "config-b",
    "datastore": {
      "type": "mysql",
      "version": "mysql-5.5"
    },
    "values": {
      "server_id": 2,
      "read_only": true
    }
  }
}

Response: 

{
  "configuration": {
    "id": "fc318e00-3a6f-4f93-af99-146b44912188",
    "name": "config-b",
    "description": null,
    "datastore_version_id": "c5ad9638-b7a1-464b-8cef-721d8c29dbf9",
    "values": {
      "server_id": 2,
      "read_only": true
    }
  }
}

Notes:

  • read_only here is used for illustrative purposes; it can be omitted or set to false on the slave/read-replica as desired.


Create Master

Request: 

POST /instances
{
  "instance": {
    "availability_zone": "us-west-1",
    "name": "product-a",
    "datastore": {
      "type": "mysql",
      "version": "mysql-5.5"
    },
    "topology": {
      "mysql": {
        "type": "master",
      }
    },
    "configuration": "b9c8a3f8-7ace-4aea-9908-7b555586d7b6",
    "flavorRef": "7",
    "volume": {
      "size": 1
    }
  }
}

Response: 

{
  "instance": {
    "status": "BUILD",
    "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
    "name": "product-a",
    "configuration": {
      "id": "b9c8a3f8-7ace-4aea-9908-7b555586d7b6",
      "name": "config-a",
      "links": [{...}]
    },
    ...
  }
}


Create Slave

Request: 

POST /instances
{
  "instance": {
    "availability_zone": "us-west-2",
    "name": "product-b",
    "datastore": {
      "type": "mysql",
      "version": "mysql-5.5"
    },
    "topology": {
      "mysql": {
        "type": "slave",
        "replicates_from": [{"id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998"}]
      }
    },
    "configuration": "fc318e00-3a6f-4f93-af99-146b44912188",
    "flavorRef": "7",,
    "volume": {
      "size": 1
    }
  }
}

Response: 

{
  "instance": {
    "status": "BUILD",
    "id": "061aaf4c-3a57-411e-9df9-2d0f813db859",
    "name": "product-b",
    "configuration": {
      "id": "fc318e00-3a6f-4f93-af99-146b44912188",
      "name": "config-b",
      "links": [{...}]
    },
    ...
  }
}

Notes:

  • type and replicates_from will be the only supported input fields, despite replicates_to being returned in a GET /instances/<id> response
  • replicates_from and replicates_to should be arrays to properly represent star + fan-in/multi-source + all-masters replication patterns (Tungsten, MySQL 5.7)
  • For now, replicates_from takes a trove instance uuid, but inevitably will need to be prefixed with resource-names to support multiple dcs and sources
  • Format of trove:dc:tenant:source:id/name, where source is instance, or backup or etc.
  • *or* additional fields like datacenter, tenant, etc. will need to be added to each dict in replicates_from


Show Instance

Request: 

GET /instances/dfbbd9ca-b5e1-4028-adb7-f78643e17998

Response: 

{
  "instance": {
    "status": "ACTIVE",
    "updated": "2014-02-16T03:38:49"
    "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
    "name": "product-a",
    "datastore": {
      "version": "mysql-5.5",
      "type": "mysql",
    },
    "topology": {
      "mysql": {
        "type": "master",
        "replicates_to": [{"id": "061aaf4c-3a57-411e-9df9-2d0f813db859"}]
      }
    },
    "flavor": {
      "id": "7",
      "links": [{...}]
    },
    "configuration": {
      "id": "b9c8a3f8-7ace-4aea-9908-7b555586d7b6",
      "name": "config-a",
      "links": [{...}]
    }
  }
}


Show Topology

Request: 

GET /instances/dfbbd9ca-b5e1-4028-adb7-f78643e17998/topology

Response: 

{
  "instance": {
    "status": "ACTIVE",
    "updated": "2014-02-16T03:38:49"
    "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
    "name": "product-a",
    "datastore": {
      "version": "mysql-5.5",
      "type": "mysql",
    },
    "topology": {
      "members": [
        {
          "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
          "name": "product-a",
          "mysql": {
            "type": "master",
            "replicates_to": [{"id": "061aaf4c-3a57-411e-9df9-2d0f813db859"}]
          }
        },
        {
          "id": "061aaf4c-3a57-411e-9df9-2d0f813db859",
          "name": "product-b",
          "mysql": {
            "type": "slave",
            "replicates_from": [{"id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998"}]
          }
        }
      ]
    }
    "flavor": {
      "id": "7",
      "links": [{...}]
    },
    "configuration": {
      "id": "b9c8a3f8-7ace-4aea-9908-7b555586d7b6",
      "name": "config-a",
      "links": [{...}]
    }
  }
}


Remove Replication (aka "Promote" to Standalone)

Request: 

POST /instances/061aaf4c-3a57-411e-9df9-2d0f813db859/topology
{
  "promote": {}
}

Response: 

TBD


Notes:

  • The PUT /instances/<id> approach requires bloat to prevent multiple unrelated fields from changing in-tandem.
  • configuration-groups uses PUT, yet things like resize use /action; no ubiquitous approach.


MySQL Master/Master


For Master/Master, the server_id must differ and the increments be offset so as to avoid collisions.

Create Configuration-Group for Master A

Request: 

POST /configurations
{
  "configuration": {
    ...
    "values": {
      "server_id": 1,
      "auto_increment_increment": 2,
      "auto_increment_offset": 1
    },
    ...
  }
}

Response: 

{
  "configuration": {
    ...
    "values": {
      "server_id": 1,
      "auto_increment_increment": 2,
      "auto_increment_offset": 1
    },
    ...
  }
}


Create Configuration-Group for Master B

Request: 

POST /configurations
{
  "configuration": {
    ...
    "values": {
      "server_id": 2,
      "auto_increment_increment": 2,
      "auto_increment_offset": 2
    },
    ...
  }
}

Response: 

{
  "configuration": {
    ...
    "values": {
      "server_id": 2,
      "auto_increment_increment": 2,
      "auto_increment_offset": 2
    },
    ...
  }
}


Create Master A

Request:

  • Same as seen in Master/Slave scenario


Response:

  • Same as seen in Master/Slave scenario


Create Master B

Request: 

POST /instances
{
  "instance": {
    ...
    "topology": {
      "mysql": {
        "type": "master",
        "join": [{"id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998"}]
      }
    },
    ...
  }
}

Response: 

{
  "instance": {
    "id": "061aaf4c-3a57-411e-9df9-2d0f813db859",
    ...
  }
}


Show Instance

Request:

  • Same as in Master/Slave scenario


Response: 

{
  "instance": {
    ...
    "topology": {
      "mysql": {
        "type": "master",
        "join": [{"id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998"}]
      }
    },
    ...
  }
}


Show Topology

Request:

  • Same as in Master/Slave scenario


Response: 

{
  "topology": {
    "id": "377d54bb-9e89-4ac3-bf29-f78c2fd4faca",
    ...
    "members": [
      {
        "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
        ...
        "topology": {
          "mysql": {
            "type": "master",
            "join": [{"id": "061aaf4c-3a57-411e-9df9-2d0f813db859"}]
          }
        }
      },
      {
        "id": "061aaf4c-3a57-411e-9df9-2d0f813db859",
        ...
        "topology": {
          "mysql": {
            "type": "master",
            "join": [{"id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998"}]
          }
        }
      }
    ]
  }
}


Remove Replication (aka "Promote")

Request: 

POST /instances/061aaf4c-3a57-411e-9df9-2d0f813db859/action
{
  "update_topology": {
    "topology": {
      "mysql": {
        "type": "master",
        "join": []
      }
    }
  }
}

*or*

PUT /instances/061aaf4c-3a57-411e-9df9-2d0f813db859
{
  "instance": {
    "topology": {
      "mysql": {
        "type": "master",
        "join": []
      }
    }
  }
}

*or*

POST /instances/061aaf4c-3a57-411e-9df9-2d0f813db859/topology
{
  "promote": {}
}

Response: 

TBD

MongoDB


Create Replica-Set



Create Initial Replica-Set

Request: 

POST /instances
{
  "instance": {
    "name": "product-a",
    ...
    "datastore": {
      "type": "mongodb",
      "version": "mongodb-2.0.4"
    },
    "topology": {
      "mongodb": {
        "type": "member",
        "replica_set": "products"
      }
    },
    ...
  }
}

Response: 

{
  "instance": {
    "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
    ...
  }
}


Notes:

  • Enforce 'replica_set' field to be provided for MongoDB, even in the case of a standalone/single instance. See http://www.mongodb.com/blog/post/dont-let-your-standalone-mongodb-server-stand-alone for reasoning.
  • The lack of a 'join' field indicates that the intention is to create a new replica-set. If an active replica-set by that name already exists, the request will be failed.
  • 'type' is 'member' vs. 'primary' because in a replica-set, the primary is dynamic and can change in an election.


Add Member to Replica-Set



Request: 

POST /instances
{
  "instance": {
    "name": "product-b",
    ...
    "topology": {
      "mongodb": {
        "type": "member",
        "join": "products"
      }
    },
    ...
  }
}


Response: 

{
  "instance": {
    "status": "BUILD",
    "id": "061aaf4c-3a57-411e-9df9-2d0f813db859",
    ...
  }
}


Notes:

  • If the replica_set field is included in addition to the join field, the request will be failed.
  • If there is no existing replica-set for the tenant by the join value, the request will be failed.
  • Will have to use db.isMaster() to determine the current master to execute replica-set commands against.
  • Will use http://docs.mongodb.org/manual/tutorial/expand-replica-set/#configure-and-add-a-member
  • Should protect against adding more than 12 members to a replica-set
  • Should protect against adding more than 7 voting members to a replica-set
  • Should return warning when number of voting members is even and there is no arbiter


Add Another Member to Replica-Set



Request: 

POST /instances
{
  "instance": {
    "name": "product-c",
    ...
    "topology": {
      "mongodb": {
        "type": "member",
        "join": "products"
      }
    },
    ...
  }
}


Response: 

{
  "instance": {
    "status": "BUILD",
    "id": "3a72ee87-cf3e-40f1-a1e1-fe8c7263a782",
    ...
  }
}


Show Instance



Request: 

GET /instances/dfbbd9ca-b5e1-4028-adb7-f78643e17998

Response: 

{
  "instance": {
    ...
    "topology": {
      "mongodb": {
        "type": "member",
        "replica_set": "products"
      }
    },
    ...
  }
}


Show Topology



Request: 

GET /instances/dfbbd9ca-b5e1-4028-adb7-f78643e17998/topology

Response: 

{
  "instance": {
    ...
    "topology": {
      "members": [
        {
          "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
          "name": "product-a",
          ...
          "mongodb": {
	    "type": "member",
	    "replica_set": "products"
	  }
        },
        {
          "id": "061aaf4c-3a57-411e-9df9-2d0f813db859",
          "name": "product-b",
          ...
          "mongodb": {
	    "type": "member",
	    "replica_set": "products"
	  },
        {
          "id": "3a72ee87-cf3e-40f1-a1e1-fe8c7263a782",
          "name": "product-c",
          ...
          "mongodb": {
	    "type": "member",
	    "replica_set": "products"
	  }
        }
      ]
    }
    ...
  }
}


Add Aribiter



Request: 

POST /instances
{
  "instance": {
    "name": "product-arbiter",
    ...
    "topology": {
      "mongodb": {
        "type": "arbiter",
        "join": "products"
      }
    },
    ...
  }
}

Response: 

{
  "instance": {
    "status": "BUILD",
    "id": "a1b62aaa-7863-4384-8250-59024141c1f8",
    ...
  }
}


Add a Delayed Member



Request: 

POST /instances
{
  "instance": {
    "name": "product-delayed",
    ...
    "topology": {
      "mongodb": {
        "type": "member",
        "join": "products",
        "priority": 0,
        "hidden": true,
        "slaveDelay": 3600
      }
    },
    ...
  }
}

Response: 

{
  "instance": {
    "status": "BUILD",
    "id": "7d8eb019-931b-4b2a-88d2-4c9f0ca1b29e",
    ...
  }
}


Notes:

  • 'type', 'replica_set', 'join', 'priority', 'hidden', and 'slaveDelay' are the only fields supported in topology.mongodb{}. All other configuration values must be set via a Configuration Group. After more thought, consider supporting 'hostname' and 'votes' as well.
  • Why isn't 'priority', 'hidden' and 'slaveDelay' in Configuration Groups you ask? This is explained in "Modifying a Replica-Set" below.


Modifying a Replica-Set


Thus far we've been able to model building a replica-set, adding an arbiter, adding a delayed secondary member, etc. Let's continue with how to modify a replica-set.

Example: 

# from http://docs.mongodb.org/manual/tutorial/configure-secondary-only-replica-set-member/#example
cfg = rs.conf()
cfg.members[0].priority = 2
cfg.members[1].priority = 1
cfg.members[2].priority = 0.5
cfg.members[3].priority = 0
rs.reconfig(cfg)

Executing these priority changes one at a time can have catastrophic results, so it must be done as a transaction (with rs.reconfig() commiting). However, without the ability to address the cluster (i.e. multiple members at once), this becomes impossible. The only backdoor solution would be to guarantee that the MongoDB user(s) presented to the cloud tenant all have the clusterAdmin role, as this would allow them to connect to the primary and execute such transactions themselves via the native client. Obviously however, granting clusterAdmin to every DBaaS user in MongoDB is unacceptable in most deployments, meaning we're stuck, unless:

Request: 

PATCH /instances/dfbbd9ca-b5e1-4028-adb7-f78643e17998/topology

{
  "instance": {
    ...
    "topology": {
      "members": [
        {
          "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
          "mongodb": {
	    "priority": 2
	  }
        },
        {
          "id": "061aaf4c-3a57-411e-9df9-2d0f813db859",
          "mongodb": {
	    "priority": 1
	  },
        {
          "id": "3a72ee87-cf3e-40f1-a1e1-fe8c7263a782",
          "mongodb": {
	    "priority": 0.5
	  }
        }
      ]
    }
    ...
  }

Response: 

{
  "instance": {
    ...
    "topology": {
      "members": [
        {
          "id": "dfbbd9ca-b5e1-4028-adb7-f78643e17998",
          "name": "product-a",
          ...
          "mongodb": {
	    "type": "member",
	    "replica_set": "products"
	  }
        },
        {
          "id": "061aaf4c-3a57-411e-9df9-2d0f813db859",
          "name": "product-b",
          ...
          "mongodb": {
	    "type": "member",
	    "replica_set": "products"
	  },
        {
          "id": "3a72ee87-cf3e-40f1-a1e1-fe8c7263a782",
          "name": "product-c",
          ...
          "mongodb": {
	    "type": "member",
	    "replica_set": "products"
	  }
        }
      ]
    }
    ...
  }
}


Notes:

  • An HTTP PATCH vs. PUT because the omission of a field or structure should not be an indication to drop/delete it.
  • All modified fields in a request will be changed transactionally in a single rs.reconfig().
  • It should now be clear why 'priority', 'hidden' and 'slaveDelay' are in topology.mongodb{} vs. a configuration-group: when a configuration-group is changed, an event is immediately triggered to update any attached trove instances. Therefore, if you have a heterogeneous mixture of configuration-groups in a replica-set, there is no way to coordinate a consolidated rs.reconfig().
  • TBD on what should be returned in the mongodb{} on a GET /instance/:id and GET /instance/:id/topology. It's a question of whether we should persist anything beyond the 'type' and 'replica_set'. If say the 'priority' is stored, you introduce the possibility of drift from the truth, but can easily return it on a GET; if it's not stored, do we prompt MongoDB for the truth on a GET, or is that too computationally expensive?


MongoDB TokuMX

  • TokuMUX will require a new datastore-version and *possibly* a new manager class (same reasoning as why Tungsten/Galera will have their own datastore-version for MySQL)
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