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| franc0a |
 Posted: Wed Dec 20, 2006 1:53 am Post subject: server - requester channel question |
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Newbie
Joined: 19 Dec 2006
Posts: 5
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I don't find in The MqCommunication Guide the behaviour of a server -requester channel when a requester try to connect to a server already connected with another requester.
Could you help me to clarify this point.
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| Vitor |
| Posted: Wed Dec 20, 2006 2:09 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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Why would a requester channel want to connect to a queue manager when a connection already exists? And how, without disconnection first?
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| Mr Butcher |
| Posted: Wed Dec 20, 2006 2:11 am Post subject: |
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Padawan
Joined: 23 May 2005
Posts: 1716
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what do you expect? a second connection?
a server is like a sender except it can be started "from outside", but it only has one xmitq to get messages from. so what should the server do? it can only send to one destination.
so if the server channel is already running you will get "remote channel not available" when doing the start of the second rqstr.
you could help yourself to clarify this by just trying it (i assume you have an mq installation where you can test).
@vitor - you may have overlooked the words "another requester"
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| franc0a |
| Posted: Wed Dec 20, 2006 5:35 am Post subject: |
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Newbie
Joined: 19 Dec 2006
Posts: 5
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thank you for your response.
I will expect that the 2nd requester disconnect the other requester when it start its channel but it seems not possible.
A Requester-sender have the same behaviour if a second requester try to communicate with a sender already connected ?
I ask this questions to know the possibilites in MQSeries about backup solution.
For exemple i have 3 Qmanager QM1 , QM2 and QM3 :
QM2 and QM3 have the same name and same queues but they are on different machines.
QM1 must be connectes with QM2 or QM3 and i want to switch QM2 to QM3.
I prefer minimize the manual interventions on the Qmanagers and i expected that the launching of the QM3 channel stop automatically the QM2 channel part.
Sorry for my bad english. |
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| jefflowrey |
| Posted: Wed Dec 20, 2006 5:59 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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I would never want QM3 to be able to interrupt anything going on with QM2.
That would be bad - that would be like database connections being able to interrupt each other.
Why would you want this?
It is not a usual occurance for people to use requestor channels, anyway. It is more usual for messages to go where they need to go immediately, rather than having to wait around for someone to ask for them.
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| JosephGramig |
| Posted: Wed Dec 20, 2006 6:14 am Post subject: |
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Grand Master
Joined: 09 Feb 2006
Posts: 1244
Location: Gold Coast of Florida, USA
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Further more, what version of WMQ are you using?
Have you considered clustering?
I would make all of the QMGR names unique and use an alias QMGR definition to handle the possibility of redirecting traffic destined for one QMGR to another, but only in a failed state and it would require human interaction and application design to make sure this will work.
Sounds like clustering might be better for you, unless the other end is not in your enterprise.
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Joseph
Administrator - IBM WebSphere MQ (WMQ) V6.0, IBM WebSphere Message Broker (WMB) V6.1 & V6.0
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| Vitor |
| Posted: Wed Dec 20, 2006 6:44 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| franc0a wrote: |
I ask this questions to know the possibilites in MQSeries about backup solution.
For exemple i have 3 Qmanager QM1 , QM2 and QM3 :
QM2 and QM3 have the same name and same queues but they are on different machines. |
If QM2 is running and QM3 is started there's a sporting chance (because the request is coming from a different IP address) a 2nd channel will try to start and the XMITQ resolution will go contact admin.
If you want failover without manual intervention buy an automated HA solution. Don't try to reinvent the wheel.
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| franc0a |
| Posted: Wed Dec 20, 2006 9:09 am Post subject: |
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Newbie
Joined: 19 Dec 2006
Posts: 5
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| JosephGramig -> if i use a cluster, how long time the modification of a QManager alias take effect on the routing ? |
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| Vitor |
| Posted: Wed Dec 20, 2006 11:38 pm Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| franc0a wrote: |
| JosephGramig -> if i use a cluster, how long time the modification of a QManager alias take effect on the routing ? |
If you use a cluster you don't need a QManager alias; messages will route according to the workload distrubtion rules (by default round-robin) where unavailable queue managers are excluded as possible destinations.
Be aware - it will take a period of time (depending on the channel settings) for the cluster to detect that a queue manager has gone down. Messages will therefore continue to be sent to it & remain there unprocessed until it is restored. This has been mitigated to an extent by the new cluster parameters available in v6 but you must still factor in if this is acceptable before using this as a solution.
It is for this reason I personally don't like clusters being used as an HA solution. Search the forum (especially the clustering section) for "stuck messages" and you'll see some threads discussing this. There's also some potentially valuable discussions on clustering as an HA solution.
Happy Reading! 
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| franc0a |
| Posted: Thu Dec 21, 2006 1:23 am Post subject: |
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Newbie
Joined: 19 Dec 2006
Posts: 5
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Ok, i will take a look on the clustering section.
Thank you |
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| franc0a |
| Posted: Thu Dec 21, 2006 5:41 am Post subject: |
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Newbie
Joined: 19 Dec 2006
Posts: 5
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| if i understand, a stuck message is a message blocked in the cluster transmission queue ? |
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| Vitor |
| Posted: Thu Dec 21, 2006 5:47 am Post subject: |
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Grand High Poobah
Joined: 11 Nov 2005
Posts: 26093
Location: Texas, USA
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| franc0a wrote: |
| if i understand, a stuck message is a message blocked in the cluster transmission queue ? |
That's a fairly good explaination. Unblocks itself once the destination queue manager comes back, and doesn't block messages destined for other queue managers.
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