Restoring a backup

[Bios-Marcel]

While dumping data into a backup is quite easy, restoring doesn't seem to be so easy.

If the storage target is of the same type, simply copying everything would work.

But if the main storage is a local directory and the backup storage is an sql server, this won't work.

I have already tried the following workflow:

CreateStorage(
    LiveStorage(localDir)
    BackupStorage(sqlServer)
).start()

CommitStuff

CommitStuff (Simulate a powerloss)

CreateStorage(
    LiveStorage(sqlServer)
).start()

While this might technically work, I haven't had the patience to actually wait for the server to start.
For some reason, booting the server with the sqlServer as the datasource is SUPER SLOW. The database is only 4 gigabytes and the server runs on the same machine, which has 32gigs of RAM and neither CPU, RAM nor disk seem to be bottlenecking.

I have also tried simply running localStorage.importFiles(sqlServer.listFiles()), but that threw an exception:

Exception in thread "Thread-0" org.eclipse.store.storage.exceptions.StorageExceptionImportFailed: Exception while reading import source org.eclipse.serializer.afs.types.AFile$Default@a22c4d8("storage/PersistenceTypeDictionary.ptd")
	at org.eclipse.store.storage.types.StorageRequestTaskImportData$Abstract.readSources(StorageRequestTaskImportData.java:137)
	at java.base/java.lang.Thread.run(Thread.java:1583)
Caused by: org.eclipse.store.storage.exceptions.StorageException: currentFilePosition = 0. nextEntityLength = 0
	at org.eclipse.store.storage.types.StorageDataFileItemIterator$Default.processInputFile(StorageDataFileItemIterator.java:255)
	at org.eclipse.store.storage.types.StorageDataFileItemIterator$Default.iterateStoredItems(StorageDataFileItemIterator.java:333)
	at org.eclipse.store.storage.types.StorageDataFileItemIterator.iterateStoredItems(StorageDataFileItemIterator.java:33)
	at org.eclipse.serializer.afs.types.AFS.execute(AFS.java:194)
	at org.eclipse.store.storage.types.StorageRequestTaskImportDataFiles$Default.iterateSource(StorageRequestTaskImportDataFiles.java:60)
	at org.eclipse.store.storage.types.StorageRequestTaskImportDataFiles$Default.iterateSource(StorageRequestTaskImportDataFiles.java:24)
	at org.eclipse.store.storage.types.StorageRequestTaskImportData$Abstract.readSources(StorageRequestTaskImportData.java:132)
	... 1 more
Caused by: org.eclipse.serializer.exceptions.ArrayCapacityException: Java technical array capacity limit of max signed 32 bit integer value exceeded: 3472328296227680304
	at org.eclipse.serializer.util.X.checkArrayRange(X.java:124)
	at org.eclipse.store.storage.types.StorageRequestTaskImportData$Abstract$ItemReader.accept(StorageRequestTaskImportData.java:212)
	at org.eclipse.store.storage.types.StorageDataFileItemIterator$Default.processBufferedEntities(StorageDataFileItemIterator.java:298)
	at org.eclipse.store.storage.types.StorageDataFileItemIterator$Default.processInputFile(StorageDataFileItemIterator.java:244)
	... 7 more

Is there any correct and not super slow way to restore a backup from a different type of storage target?

I think this is kind of missing in the documentation.

Maybe there's also something "wrong" with my demo case?

I have this structure:

StorageRoot{
    A {
        List<byte[]>
    }
    B {
        List<byte[]>
    }
    C {
        List<byte[]>
    }
}

Is there any reason for this to be extremly slow?