What are the essentials of distributed real-time systems? A distributed real-time system composes two challenging sets of properties which are imposed by the problem domain or the solution domain (or both.) Distributed A distributed system links a number of independent computing entities with local properties by way of a communication mechanism. As a consequence, algorithms … Read more
You missed something in step 7. When C processes accept 100:b it sets its state to C(100:b,100). By accepting a value the node is also promising to not accept earlier values. Update. I’ve been thinking about this all month because I knew the above answer was not absolutely correct. What’s more I looked through several … Read more
check also GlusterFS Edit (Aug-2012): Ceph is finally getting ready. Recently the authors formed Inktank, an independent company to sell commercial support for it. According to some presentaions, the mountable POSIX-compliant filesystem is the uppermost layer and not really tested yet, but the lower layers are being used in production for some time now. The … Read more
A message queue is a data structure, or a container – a way to hold messages for eventual consumption. A message broker is a separate component that manages queues.
You already know about method calls. What if the object that you want to invoke the method on is on a different computer? You use RMI to send the call from one computer (client) to the other (server). The client will wait (or “block”) until the result comes back from the server. This is called … Read more
API Gateway and Load Balancer are 2 different things. Load Balancer -> Its a software which works at protocol or socket level (eg. tcp, http, or port 3306 etc.) Its job is to balance the incoming traffic by distributing it to the destinations with various logics (eg. Round robin). I doesn’t offer features such as … Read more
A message queue is a data structure, or a container – a way to hold messages for eventual consumption. A message broker is a separate component that manages queues.
tp90 is a maximum time under which 90% of requests have been served. Imagine you have times: 10s 1000s 100s 2s Calculating TP is very simple: sort all times in ascending order: [2s, 10s, 100s, 1000s] find latest item in portion you need to calculate. For TP50 it will ceil(4*.5)=2 requests. You need 2nd request. … Read more
It is very easy to misunderstand the CAP properties, hence I’m providing some illustrations to make it easier. Consistency: A query Q will produce the same answer A regardless the node that handles the request. In order to guarantee full consistency we need to ensure that all nodes agree on the same value at all … Read more
General In general, the goal of the bulkhead pattern is to avoid faults in one part of a system to take the entire system down. The term comes from ships where a ship is divided in separate watertight compartments to avoid a single hull breach to flood the entire ship; it will only flood one … Read more