FAQ and Manuals about cloudn


This page shows FAQs of RDB.
When you click the question, the answer will be displayed.

Do you provide the SDK or command line tool?

No. We do not provide it currently. Refer to the API manual for use. We are planning to provide the SDK in future.

Does the service stop when performing failover?

Yes. The service stops while failover is performed from Master to SubMaster. We will provide MySQL ReadReplica. Using ReadReplica does not stop the reference service.

What is the specification of machine which operates a DB instance.

We provide four instance classes below as a RDB service.
・vDB1 db.m1.small (1vCPU, memory 2GB)
・vDB2 db.m1.medium (2vCPU, memory 4GB)
・vDB4 db.m1.large (4vCPU, memory 8GB)
・vDB8 db.m1.xlarge (8vCPU, memory 16GB)

The RDB instance fails to be created after API access key update.

When you create a RDB instance on the RDB Console after updating the API access key and secret key of “Common services” used in RDB, you fail to create it.

This is caused by caching the key information before update. Clear the cache information of browser after update.

Can I specify the Zone which establishes a DB instance?

You can specify it in the Single-Zone configuration but cannot specify it in the Multi-AZ configuration.

How to access to the MySQL server on Apache from the Compute instance.

The created instance has SELinux enabled in the initial state. Use these commands to configure to allow the access to database.

# setsebool -P httpd_can_network_connect_db 1

What is the size of available Storage?

We provide two size menus below as a RDB service.
・ 100GB

What is the API request with causing the service stop?

The following requests cause the service stop. ・Use ModifyDBInstance to change the instance class.
・Use ModifyDBInstance to change the data disk size in the Single-Zone configuration.
・Use RebootDBInstance to reboot.

Is the service stopped when increasing the Storage size?

In the Multi-Zone configuration, the size can be increased without stopping the service. In the Single-Zone configuration, the service stops when increasing the size.

Is the implementation date of maintenance works provided by the service provider decided?

The maintenance works planned of RDB service is performed on Thursday at 15:00-20:00 (JST).

What is the available MySQL version?

Currently we provide “MySQL 5.5.28″ only. We will expand gradually the version in future.

Can I use AWS SDK or CLI tool?

No. We don’t support them.
Cloudn technical blog

We describes Rudy tool for reference in the following site:

What is the maximum value which can hold backups?

We will provide the backup function in future (under the following conditions)

You can use CreateDBInstance to specify the function when creating a DB instance initially. The range specified is 0 to 35 days. If you do not backup, the value is set to 0 days. 35 days is the maximum period for holding backups.

SubMaster is not displayed in GUI in Multi-AZ.

Only the Master is displayed. If MultiAZ is “true” and the “status=available” appears, SubMaster is created.

Can I set the maintenance window freely?

You cannot specify Thursday (UTC). The end time calculated from the start time is fixed to 300 minutes.

When I click the “DB instance” menu on the left on GUI site of RDB, the screen returns to the RDB dashboard. What should I do?

Clear all caches in your browser and then retry. After that, if the event continues, contact us from the support portal.

When does the service stop during operations on the maintenance window?

The DB instance service stops in the following cases:
・Users perform the maintenance with causing service stop by themselves.
・The service provider performs the maintenance with causing service stop.
・Also API reception or GUI service stop occur in the following situations. ・The service provider performs the maintenance with causing service stop.

When do you start to charge the RDB DB instance?

When creating a new DB instance (CreateDBInstance), you are not charged until the “status=available” appears. Charging starts as soon as the “status=available” appears.

The normal status when creating a new DB instance moves from “creating” to “available”.

The status moves from “creating” to “failed” in the event of failure. Therefore no charged in the event of abnormality.

Do you provide the SLA?

No, we don’t provide the SLA.

Must I cancel Cloudn after all DB instances are deleted when I cancel?

Not necessary.
All DB instances being used are deleted as soon as you cancel Cloudn and charging stops.

What is Cloudn Relational Database (RDB)?

This is the service in which you can setup the relational database on the cloud easily and operate / expand it. This liberates the customers from database (DB) management task hassles and provides the reasonable function which allows scale modification flexibly. This allows the customer to focus on the application development or business.

What is AZ (Availability Zone) of Multi-AZ?

In the RDB service, Availability Zone is just called as Zone. In order to have a compatibility with API parameter of AmazonRDS, AZ is used as the specified parameter.

(Availability) Zone is a place created in order to quarantine a different failure which occurred in other (Availability) Zone. Each (Availability) Zone is running on the physically-independent infrastructure. Those zones are physically located in the different locations. Therefore in the event of disaster such as fire or flood, only one zone is affected.

I normally use the DB instances but the status shows “failed”. Is this charged?

Charging continues.

Request ModifyDBInsntace. When the request is performed, the status is changed to “modifying”. When the request contents are performed normally, the status is back to “available”. When the status is not back to “available”, contact us from the support portal.

What is charged when using RDB ?

Only the used resource is charged. We do not provide the bottom fee or setup fee.
・ We charge based on DB instance class and usage time. Use of DB instance for less than one hour is charged as one hour.
・Backup storage is the storage to save user’s automatic-backup data or snapshot data. The usage rate of this backup storage is also charged (Pay-as-you-go system).

What is the benefit in Multi-AZ configuration?

Main benefit establishing a DB instance as Multi-AZ configuration is to strengthen the database robustness and availability.

Establishing a DB instance as Multi-AZ configuration allows to protect the customer’s data when unexpected events like DB instance component failure and service failure in one Availability Zone occur.

For example, when the storage volume on the primary has a failure, Amazon RDS automatically starts failover for the standby which keeps the customer’s database update in the complete state. Compared with the Single-Zone configuration, it increases the robustness of data.

In the Single-Zone configuration, the user must start the restore operations. The user cannot use the updates generated after the restorable latest time (within 5 minutes in past).

When does charging the RDB DB instance stop?

Charging the DB instance stops when “status=deleting” appears.

When you execute DeleteDBInstance, the “status=deleting” appears. If deletion is not completed due to any failure after that, the status becomes “failed” but charging continues.

When deletion is completed successfully, the said DB instance is not shown on the GUI screen. If you try to confirm the instance with DescribeDBInstance, you receive no response.

When does the charging the RDB start?

Charging starts as soon as the DB instance is available. Charging continues until the DB instance is deleted?

What is the effect on performance when establishing the DB instance in the Multi-AZ configuration?

As the result of data replication from Master to SubMaster, the Master in the Multi-AZ configuration has lower performance than the Master in the Single-Zone configuration.

Can I shell login to RDB instance?

No you can’t.
You can’t login to DB server. You also can’t edit my.cnf and process option for MySQL server running.
You only can connect to the MySQL database with MySQL command.

I want to use the RDB service. What should I do?

You can use the online application on Web easily. http://www.ntt.com/cloudn/

Confirm the service contents on the above site and then apply for it.

Can SubMaster be also used as ReadReplica?

No. it can’t. SubMaster does not support the reading request. The Multi-AZ configuration is designed so as not to provide the benefit by expanding the reading function but to strengthen the database availability and robustness.

What is the function which can be operated from GUI?

You cannot use all functions from GUI.
You can use the functions corresponding to API functions below from GUI.


Also you can use the following function directly from RDB API.


We will gradually add functions in future.

When does the failover occur in the Multi-AZ configuration?

Detect the most popular failure scenario and then perform failover automatically. Concretely detect the following scenario and perform failover.
・Network connection for Master is disconnected.
・DB instance failure while Master is running.

In the following scenarios, Master Zone is switched by the different function from the failure-response failover function. ・When changing a DB instance.
・Rebooting execution when Force Failover is enabled.

The recommended browser is Firefox. Abnormal behaviors may occur when you use other browser software, e.g. the screen is corrupted.

Can the users perform failover by themselves?

Yes. They can use the API of “RebootDBInstance” to switch to SubMaster.

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