What happens if the connection to the Cloud is down for a very long time? Does the Self-Hosted Agent work at all? Is it possible to start integrations in a Self-Hosted Environment?
The Agent continues to execute integrations while the Service Bus connection to the cloud is down, remote Subprocesses cannot naturally be executed while the connection is down. The Agent will start storing log data locally until it can reconnect to the Service Bus. How long is a very long time? At some point, the Agent will run out of space for the log data and cannot continue functioning.
What kind of backups are from the Cloud Frends Environment? If a PaaS Agent completely dies, how it can be recovered? How long does it take?
PaaS Agents use SQL Azure, if the Agent VM is destroyed it can be recreated and configured to use the existing database. This usually takes less than half an hour. If there are customizations to the VM such as VPNs or certificates, those need to be handled separately. The PaaS Agents are supposed to be kept as transient as possible to be able to recreate them as easily as possible.
If a Self-Hosted Agent completely dies, how it can be recovered?
That depends on the on-prem admins but reinstalling the Agent on a new machine (VM or otherwise) and synchronizing it will re-establish it from the view of Frends. Again, any customization, such as firewall settings, certificates, etc; will have to be reconfigured unless the machine is recovered from a backup.
What if Frends Configuration store or Log store databases crash?
The Configuration store is the most important database for the survival of the Frends installation, it is backed up on Azure and off-site. The Log store is backed up in Azure.
If Frends Configuration store, Log store databases, or core services crash, the Agents continue their operation. If Service Bus is still operational, it may fill up and stop operating, if messages are not processed Service Bus fills up.
What if Frends Agent databases crash?
The Agent databases usually can be recreated at will, but in the cloud, they are backed up in Azure. If the Agent database is recreated File Triggers might be re-executed if the files are not moved from their directories, which should be avoided anyway.
If Agent databases crash the Agent can not execute Schedule or File Triggers. If a connection to the database is lost Agent will continue to execute integrations based on its cache and tries to reconnect to the database. This state can not be sustained long and for example, restarting the Agent will clear its cache.
What if the Service Bus database crashes?
If Service Bus is not operational Frends Agents and core can not communicate with each other. Agents will continue to execute integrations and store log messages to their own database which may fill up the disk at some point.
What if everything crashes?
In a total destruction scenario, the Frends Environment can be recreated from the Configuration store database backup that is kept off-site.