Broker setting - Maximum Client Instances

Maximum client instances

The maximum number of client connections that the broker can support concurrently. The default is 512, which is high enough to ensure that the number of client connections is virtually unlimited. Realistically, however, the system-level resources needed to support an unlimited number of clients might be exhausted before this limit is reached. If you see broker log entries that contain Exception Messages for "out of space" or "OutOfMemory" you may need to reduce the maximum number of client connections to a more reasonable value. Note, however, lowering this value can cause some client requests to be rejected ("Exceeded Max Clients"). Configuring and starting multiple brokers to handle higher client loads will alleviate the problem.

You can find this information in the help of the Progress Explorer itself.

>Is this a hard/soft maximum?  i.e. will it get increased dynamically if needed or will we have to set it to a number that we think we will need?

It is a hard maximum.

>It is set to 500 atm.

>If we have 5 AppServers set up how does this affect the max no of clients?  i.e. do we have 500 on each AppServer and so 2500 (ish) across all 5 or 500 across all 5?

It is a broker setting, therefore applies to all agents in total.

Thanks again for the help!

I have one more question.

Since we set up the appserver we have found that the server itself seems to be taking up broker client sessions.

On our dev version we have 7 users and we are the only people who use it.  On the server status under Active Clients it shows (66, 69).  In the server log I can see the connections being made ...

[09/07/20@15:40:36.883+0100] P-002789 T-000001 2 AS AS Application Server connected with connection id: 10.1.1.6::dev-vphiredesk::6500::dcd66acc52df8689:7a84e4:122981d2676:-7209. (8358)

but not being disconnected.

Running netstat on the server shows lots of ...

vpsun1.43125         vpsun1.app-dev-vphiredesk 49152      0 49152      0 ESTABLISHED
vpsun1.app-dev-vphiredesk vpsun1.43125         49152      0 49152      0 ESTABLISHED

Is this normal?

Thanks again for any help!

Oliver

Hi Oliver,

In my experience this is an indication of clients not disconnecting properly. That can happen for example when a client switches off the machine or loses the network connection. In that case the broker thinks the client is still connected until a timeout occurs. This timeout is a standard TCP timeout typically 1 hour. So for example in the evening you should see the number go down again.

If you have only 7 clients and the AppServer reports 66 active clients I would think you either have a network problem or clients are connecting more than once (even though you think otherwize). In any case you need to look into this further since with this problem you can easily inadvertedly reach the maximum.

Thanks for the response.

I'll definitely have a look at what's going on.

The only puzzling thing is that when a client connects it outputs to a log to let us know and the netstat on the server shows something like...

ServerName.app-dev-vphiredesk ClientPCName.vpplc.com.1148 65464      0 49640      0 ESTABLISHED

I have checked the log and there are no logs of connections (although I realise that things might be going on without logs being produced) but the main concerning issue is the netstat showing..

ServerName.app-dev-vphiredesk ServerName.43070         49152      0 49210      0 ESTABLISHED

This is suggesting that the server itself is ...

Err...

I think I just thought of what might be going on...

Back in a sec

Brilliant!

Found it!

We had a webserver that was still relying on old code to close the AppServer.

Just have to change an include file and it should sort it!

Thanks again!

Hi,

I am not able to understand the exact reasons for which it is recommended that the maxClientInstances may not be increased to a very high value:is it due to space or other resource constraints?

How do i find out what should be the optimum value of maxClientInstances?

I have configured Nameserver loadbalancer. In this scenario, would the maxClientInstances be applicable to all the brokers collectively under the group or to the each individual broker. I understand that it is a application broker property, but would queuing and rejecting of additional requests be handled by broker or nameserver?

TIA.