Deadlock detection in Distributed systems
In a distributed system deadlock can neither be prevented nor avoided as the system is so vast that it is impossible to do so. Therefore, only deadlock detection can be implemented. The techniques of deadlock detection in the distributed system require the following:
- Progress –
The method should be able to detect all the deadlocks in the system.
- Safety –
The method should not detect false or phantom deadlocks.
There are three approaches to detect deadlocks in distributed systems. They are as follows:
- Centralized approach –
In the centralized approach, there is only one responsible resource to detect deadlock. The advantage of this approach is that it is simple and easy to implement, while the drawbacks include excessive workload at one node, single-point failure (that is the whole system is dependent on one node if that node fails the whole system crashes) which in turns makes the system less reliable.
- Distributed approach –
In the distributed approach different nodes work together to detect deadlocks. No single point failure (that is the whole system is dependent on one node if that node fails the whole system crashes) as the workload is equally divided among all nodes. The speed of deadlock detection also increases.
- Hierarchical approach –
This approach is the most advantageous. It is the combination of both centralized and distributed approaches of deadlock detection in a distributed system. In this approach, some selected nodes or clusters of nodes are responsible for deadlock detection and these selected nodes are controlled by a single node.
Can deadlocks be prevented in distributed systems?
Deadlocks cannot be completely prevented in distributed systems due to their inherent complexity, but some techniques such as resource allocation strategies and careful design can reduce the likelihood of deadlocks occurring.
What happens when a deadlock is detected in a distributed system?
When a deadlock is detected, the system must take action to resolve it. This can involve releasing resources, aborting processes, or other strategies to break the deadlock.
How do centralized, distributed, and hierarchical deadlock detection approaches differ?
Centralized approaches rely on a single node to detect deadlocks, while distributed approaches distribute the detection workload among multiple nodes. Hierarchical approaches combine elements of both, with selected nodes responsible for deadlock detection and controlled by a single node.
What are the advantages and disadvantages of each deadlock detection approach?
Centralized approaches are simple to implement but can suffer from single-point failure and excessive workload. Distributed approaches avoid these problems but can be slower due to communication overhead. Hierarchical approaches offer the benefits of both approaches but may be more complex to implement.