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MQSeries.net Forum Index » General IBM MQ Support » Client connections hangs every few days - MQ 5.3 on Linux -

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QMan
PostPosted: Wed Oct 05, 2005 6:47 am    Post subject: Client connections hangs every few days - MQ 5.3 on Linux - Reply with quote

Novice

Joined: 25 Jun 2003
Posts: 11

Hi,

We have a linux (red Hat ES 2.1) with MQ 5.3, CSD 5. It connects to other MQ QMs and also runs 2 listeners (2 different ports) - one for internal QMs and other listener for External MQ lient conn.
I have about 20 Server Conn. channels and each of them have a channel security exit. For logging and security / audit I have each client connect using unique svr conn. My Qm.ini has these settings - (I think they are more than enough)
Channels:
MaxChannels=300
MaxActiveChannels=300
TCP:
ListenerBacklog=250

EVerything works fine, but at random - once a week or sometimes twice a week - the client connections hang - I have a monitoring set up (I do client connection from 1 of our servers and i get alert in case of errors). AT these time, the QM itself is ok, but the client connections hang. I have to restart the QM. I see no fdc files nor any errors in /var/mqm/error or the errors under qmgr..
I have checked the kernel settings etc, all seem ok (as per mq recoomendations). Am I doing something totally crazy - by creating different svrconn channels? should I use only 1 svrconn channels? I see at any time # of mq process (ps -aef) ~ 120 - 140. also the # of amqrmppa process (client) is ~ 30 . I do have 1 rouge client - who do not close conn - (they are going to fix it) but rest all of them use our java client mq program - which opens, puts/gets and closes..
this client who is not closing the conn is a new one, but this problem happened before also, so I cannot pin it on him..
any suggestions? sorry for the long post.
thanks!
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Q Man
Websphere MQ Specialist, MQ Workflow Solun. Expert
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fjb_saper
PostPosted: Wed Oct 05, 2005 12:48 pm    Post subject: Reply with quote

Grand High Poobah

Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY

Qman -- this sounds like a network problem.

Sometimes due to network problems clients try to access the qmgr, open the (svrconn) channel, loose the connection and cannot close the channel.
Increasing the number of max channels would not solve the problem in this case.

We get it once in a blue moon. You do however not need to reboot the machine or recycle MQ.

Just check which is the offending channel (svrconn) and shut it down (stop channel....).
It might take a few minutes after all at that point it might be open over a 100 times. Make sure the network problem is resolved and restart the channel.

Depending on your config you should have 1 (svrconn) channel per application / application type / location (network problems)

So if you have your svrconns distributed either by apps or by location chances are when 1 location goes bad (net problems) you would only have to recycle one channel. Same goes for 1 app if the channels are split by app. If you do the double split however you may have to recycle all app channels for 1 location or all locations for a specific app...

The other main reason to use a different channel is security (see security exit and mcauser).

Enjoy
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QMan
PostPosted: Wed Oct 05, 2005 1:10 pm    Post subject: Client connections hangs every few days - MQ 5.3 on Linux Reply with quote

Novice

Joined: 25 Jun 2003
Posts: 11

fjb_saper,
Thanks for the reply. 1 thing I forgot - we have 2 listeners -
port1 - internal
port 2 - external;
yes we have separate svrconn for separate apps.
but all the clients hang.

But 80% external clients connect thru' vpn (they have a port to port vpn access). some are internal, but remote location, so they are already in network.
Can this be some network/vpn issue, which messes up the mq listener..
I know we are going into network relam, but everone thinks it is MQ issue..
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Q Man
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fjb_saper
PostPosted: Wed Oct 05, 2005 1:18 pm    Post subject: Reply with quote

Grand High Poobah

Joined: 18 Nov 2003
Posts: 20756
Location: LI,NY

VPN or no VPN no difference.

As soon as the connection is not "bindings" you may have network problem interferrence...

Sometimes it is a good idea to have a qmgr at a "remote" location to act as concentrator and have qmgr to qmgr channels for that location. It minimizes some of the network problems...

Enjoy
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