According to their site, it says connection limit is 200 (premium 2), does that mean that only 200 clients can use my redis db at a time?
It means your app can open 200 connections to Redis at one time - a client is not == a user to your site. It's typically a process such as web defined in your Procfile - the more processes you run the more connections you will need.
Related
We want to limit the number of connections for our rest web service.
We are using spring boot with jetty as server.
We have configured below settings :
#rate limit connections
server.jetty.acceptors=1
server.jetty.selectors=1
#connection time out in milliseconds
server.connection-timeout=-1
Now, as you can see that there is no idle timeout applicable for connections.
Which means a connection once open will remain active until it is explicitly closed.
So, with this settings, my understanding is that if I open more then 1 connection, then I should not get any response because the connection limit is only 1.
But this does not seem to be working. Response is sent to each request.
I am sending request with 3 different clients. I have verified the ip address and ports. They all are different for 3 clients. But all 3 remains active once connection is established.
Any experts to guide on the same?
Setting the acceptors and selectors to 1 will not limit the max number of connections.
I suggest you look at using either the jetty QoS filter, or the Connection Limit jetty module.
I am a beginner with websockets.
I have a need in my application where server needs to notify clients when something changes and am planning to use websockets.
Single server instance and single client ==> How many websockets will be created and how many connections to websockets?
Single server instance and 10 clients ==> How many websockets will be created and how many connections to websockets?
Single server instance and 1000 clients ==> How many websockets will be created and how many connections to websockets?
How do you scale with websockets when your application has a 1000’s of user base?
Thanks much for your feedback.
1) Single server instance and single client ==> How many websockets will be created and how many connections to websockets?
If your client creates one webSocket connection, then that's what there will be one webSocket connection on the client and one on the server. It's the client that creates webSocket connections to the server so it is the client that determines how many there will be. If it creates 3, then there will be 3. If it creates 1, then there will be 1. Usually, the client would just create 1.
2) Single server instance and 10 clients ==> How many websockets will be created and how many connections to websockets?
As described above, it depends upon what the client does. If each client creates 1 webSocket connection and there are 10 clients connected to the server, then the server will see a total of 10 webSocket connections.
3) Single server instance and 1000 clients ==> How many websockets will be created and how many connections to websockets?
Same as point #2.
How do you scale with webscokets when your application has a 1000’s of user base?
A single server, configured appropriately can handle hundreds of thousands of simultaneous webSocket connections that are mostly idle since an idle webSocket uses pretty much no server CPU. For even larger scale deployments, one can cluster the server (run multiple server processes) and use sticky load balancing to spread the load.
There are many other articles like these on Google worth reading if you're pursuing large scale webSocket or socket.io deployments:
The Road to 2 Million Websocket Connections in Phoenix
600k concurrent websocket connections on AWS using Node.js
10 million concurrent webSockets
Ultimately, the achievable scale per a properly configured server will likely have more to do with how much activity there is per connection and how much computation is needed to deliver that.
I understand that two sessions cannot use a connection at the exact same time. But I had thought it was possible for multiple sessions to share the same connection or pipe, similar in principle to a threaded application, where processing of execution is time-sliced.
The reason I bring this up is I'm somewhat perplexed by how the F5 load balancer manages connections, in relation to application sessions. I have a web server which connects to the F5, which load balances 2 application servers:
Client (i.e. laptop) --> Web Server --> F5 Load balancer for app servers --> (app server 1, app server 2)
I was looking at the number of connections on the F5 load balancer the other day and it showed 7 connections to app server 1 and 3 connections to app server 2; 10 total connections. But the actual application had hundreds of sessions. How could this be? If there are 1000 sessions, let's say, that averages out to 1 connection per 100 sessions. Something doesn't add up here, I'm thinking.
Can and does the F5 load balancer distinguish between inbound connections and outbound connections? If so, how can I see both inbound and outbound connection? I'm thinking that, perhaps, there are 10 inbound connections from the web server to the load balancer and 1000 outbound connections (because 1000 sessions) to the app servers.
I'm thinking it should be possible to queue or share multiple sessions per connections but maybe that's not how it works, particularly with load balancers. Any help making sense of all of this would be most appreciated. Thank you.
If you were using the OneConnect feature, this is exactly what it's intended for. The BIG-IP manages an internal session state for these connections and can reuse and maintain server-side sessions for multiple external connections.
Useful for potentailly bulky applications but can cause issues if you have internal applications that reuse unique keys for session state (Java is a good example).
SOL7208 - Overview of the Oneconnect Profile
Let's say I've got 2 Stock ticker servers that're pushing quotes to web browser clients. the 2 servers sits behind a load balancer (Round Robin mode).
consider the following scenario:
client A subscribe to Google stock on Server1 like so: Groups.Add(Context.ConnectionId, "Google");
client B subscribe to Yahoo stock on Server2:Groups.Add(Context.ConnectionId, "Yahoo");
client C subscribe to Google stock on Server2:Groups.Add(Context.ConnectionId, "Google");
Now both servers are already synced with the stock market so when a stock gets updated they both get the update at real time.
my question is:
when server2 push a new update like so:
Clients.Group("Google").tick(quote);
who are the clients it will send the message to? will it always be client C? I guess not, we have a load balancer in between so the connected clients at a given time may change, right? it may me C now, but next tick it can be clients A&C or only A. A web sockets's connection suppose to stay open so how does the load balancer will handle that, will it always forward the connection from 1 client to a specific server?
backplane won't help me here, because my 2 servers already synced and will send the same messages at the same time. so if I'll force them to route their messages through the backplane to the other server it will end up with duplicate messages to the clients like so:
server1 gets ticker X to Google at 10:00 --> route to backplane --> route to server 2
server2 gets ticker X to Google at 10:00--> route to backplane --> route to server 1
server 1 sends 2 X Google tickers to his clients
server 2 sends 2 X Google tickers to his clients
OK, eventually I have synced all group subscriptions thorugh a shared cache (Redis) so all servers knows all users and their subsciptions. this way each server will know his current clients registerd groups, and will push the relevant data.
Update:
After much thought this is what we've ended up doing:
load balancer will assign a sticky session to an incoming connection so each new connection will have a one constant SignalR server.
section 1 will make the Redis sync redundant as each server will know all his clients.
In case of a server\network failure, the SignalR client will reconnect and will be assigned with a new(in case of a server failure) server by the load balancer.
After a reconnect the SignalR client will resubscribe with the relevant stocks(May be redundant if the failure was on the network and the load balancer redirect it to the old SignalR server, but I'll live with that).
Hi Our EMS server is used by other clients for putting message. But some time they dont close connections and number of connections is reaching maximum limit of the server. Is there any way where we can restrict the number of connections for the client based on emsusername provided to the client or based on the host name from where client is creating connection. Is there any configuration we can do for client specific connections restriction.
No, there is no such provision in EMS server or client libraries where you can restrict the number of consumer/producer clients based on their user names or other properties. You can have a look at the JAAS and JACI provision supported by EMS which can be used to write your own JAVA authentication custom modules which run in JVM within EMS server. You can find more information about JAAS and JACI on Oracles documentation site.
Have you looked into the server_timeout_client_connection setting ?
From the doc :
server_timeout_client_connection = limit
In a server-to-client connection, if the server does not receive a heartbeat for a
period exceeding this limit (in seconds), it closes the connection.
We recommend setting this value to approximately 3 times the heartbeat interval, as it is specified in client_heartbeat_server.
Zero is a special value, which disables heartbeat detection in the server (although
clients still send heartbeats).