If a migration takes a very long time, what can be the cause, and how can we investigate and mitigate the problem if there is any?
What is considered too long for a migration of an element?
The size of the database data included in the DELT package significantly impacts the duration of the migration. Some elements may contain hundreds of thousands of alarm properties, each of which must be imported. This process can be very time-consuming, making it impossible to provide an accurate estimate.
During the migration, activities are logged in the DELT log file in Cube. On the source DMA, the logging “Starting Export” is added at the start of the activity, and “Finished Export” confirms its completion. Additionally, DataMiner logs the file copying process between the start and finish of the export.
Subsequently, the import begins on the destination DMA. The logging “Starting Import” indicates the start of the import, and any subsequent errors are logged. The import is in progress as long as no errors are generated or an indication of completion is provided. It is normal to see “Handling Import instruction” in the logging, which indicates that the migration is still in progress and specifies the import action being performed. The logging “Import finished” signifies the completion of the activity.
During the element migration, the export package is created on the source DMA in ‘C:\Skyline DataMiner\System Cache\DELT\Export’. This file can be used to recover the element should the system encounter an issue preventing the completion of the migration. If the migration takes longer than expected, please review the DELT logging in Cube. You may raise a ticket with Techsupport if the logging is inconclusive or if you would like to confirm if there is any cause for concern.
We do not recommend our users to modify this package without consultation. Please reach out to Techsupport, and they will assign someone to assist you with this process
In Q3 of this year, we will launch the Swarming feature (https://docs.dataminer.services/user-guide/Advanced_Functionality/Swarming/Swarming.html?), which will make this process seamless.
The cause can be due to a variety of reasons.
The migration feature uses DELT, so the same reasons a DELT export can take a long time apply here.
Off the top of my head:
- Lots of data (alarms, trending, elementdata) in the database that needs to be moved.
- Lots of properties that need to be transferred.
- (Partial) inclusion in a lot of other objects (services, redundancy groups,...) that need to be updated.
Perhaps taking a DELT export could give some insight in why an element takes a long time. Both the UI and Skyline DataMiner\Logging\SLDELT.txt might show something useful.
Say there are too many alarms, can I then change the export zip file and remove the alarm data before importing it again?
And how do I initiate the import after adjusting the export zip?