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November 20th, 2024
Machine translation is used partially for this article. See the Japanese version for the original article.
This time, we introduce the feature for configuring the Service Startup Delay Time of EXPRESSCLUSTER X, along with how to calculate the appropriate delay time.
This article is a revised edition (2024 edition) of a previous article. The previous article lacked some considerations regarding the Service Startup Delay Time, so a new article has been created.
Therefore, regardless of the version of EXPRESSCLUSTER X, please refer to this new article instead of the previous one.
If the startup delay time for the services of EXPRESSCLUSTER X is not appropriately set, the following issues may arise:
If you want to trigger a failover by restarting the server, but the cluster service startup on the restarted server completes within the combined time of the Heartbeat Timeout and Heartbeat Interval, the peer server will interpret the heartbeat as continuous, failing to recognize the restart, and thus failover will not occur.
To avoid this issue, it is necessary to delay the startup time of EXPRESSCLUSTER X services so that it exceeds the combined time of the Heartbeat Timeout and Heartbeat Interval.
Therefore, please add the following time to the Service Startup Delay Time:
When the standby node in EXPRESSCLUSTER X detects a heartbeat loss from the active node, it executes Network Partition Resolution (hereinafter called NP resolution). For more information on NP resolution, please refer to the following article.
Please note that the DISK NP resolution resource is a feature available only for the Windows version and does not need to be considered for the Linux version. For more details on the DISK NP resolution resource, please refer to the following Reference Guide.
In EXPRESSCLUSTER X 5.0 or later, the Forced stop resource to prevent both-system activation is provided by default. For details about the Forced stop resource, please refer to the following article.
When using the Forced stop resource, if the conditions for a forced stop are met, a failover will occur after the active node is forcibly stopped by the standby node to prevent both-system activation. Since the forced stop process utilizes the functions of the server, virtual platform, or cloud platform to stop, it may take time to stop the active node server depending on the situation.To avoid this issue, it is necessary to delay the startup time of EXPRESSCLUSTER X services on the active node until the Forced stop resource completes the forced stop.
Therefore, please add the following time to the Service Startup Delay Time:
When you power on the shared disk and server to start the cluster system, if the shared disk is not fully powered on in time for the service startup process of EXPRESSCLUSTER, and EXPRESSCLUSTER starts without recognizing the shared disk, the resources that use the shared disk will fail to activate.
Therefore, it is necessary to set the Service Startup Delay Time to be longer than the following time:
This section explains the final calculation method for determining the "Service Startup Delay Time" for each cluster configuration explained in Section 1.
First, add together the values explained in Sections 1.1 to 1.3 as follows:
After the OS has started, verify that the EXPRESSCLUSTER X service starts after the number of seconds specified in the Service Startup Delay Time has elapsed. In this verification, we are using EXPRESSCLUSTER X 5.0 (internal version: Windows 13.00, Linux 5.0.0-1) and have set the Service Startup Delay Time to "300 seconds" as a test.
After restarting the OS, verify the time when the OS started and the time when the EXPRESSCLUSTER X service started.
Since the verification procedures differ between Windows and Linux, the procedures for each are described separately.
To verify the server's startup time in Windows, check the "System" event log.
Next, check the "Application" event log for the message indicating that the cluster service has started, along with the timestamp.
Refer to the following log entry:
"Cluster service has been started properly."
In this verification, it can be confirmed that the cluster service startup completes 5 minutes and 34 seconds (334 seconds) after the OS startup time.
* Note that there may be a slight variation in the timestamps recorded in the logs.
To verify the server's startup time in Linux, use the following command:
Next, use the following command to check the timestamp when the EXPRESSCLUSTER X service started:
This article introduced the feature for configuring the Service Startup Delay Time of EXPRESSCLUSTER X, along with how to calculate the appropriate delay time.
By utilizing this feature, you can easily configure the service startup delay for EXPRESSCLUSTER X from the Cluster WebUI without delaying the OS startup time. We encourage you to consider using this feature.
If you consider introducing the configurations described in this article, you can perform a validation with the trial module of EXPRESSCLUSTER. Please do not hesitate to contact us if you have any questions.