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| jrjoe |
 Posted: Tue Mar 16, 2004 8:26 am Post subject: MQ Clustering with Content Switch |
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Acolyte
Joined: 20 Jan 2003
Posts: 60
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I have 2 AIX boxes that will have Queue Managers on them in a Cluster.
These AIX boxes will be located behind a network content switch which will load balance the 2 boxes.
My question is will MQ clustering work in this enviorment?
If I take down one of the boxes all traffic will be routed to the other box thru the content switch.
Has anyone worked with this type of setup ?
Any advice or help will be much appreciated.
Thanks
Joe |
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| bduncan |
| Posted: Tue Mar 16, 2004 9:57 am Post subject: |
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Padawan
Joined: 11 Apr 2001
Posts: 1554
Location: Silicon Valley
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I very much doubt this would work out of the box.
Clustering, and MQSeries in general depends on channels that are defined between two distinct queue managers.
If a channel is defined between QM1 and QM2 and I send a message across that channel, but in the meantime your load balancer has rerouted all QM2's inbound network traffic to QM3, QM3 is not going to just accept the message. That is because when a message is placed on the transmission queue, the destination queue manager id is placed in the transmission header of the message, and that won't match the queue manager that the message ultimately gets routed to.
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Brandon Duncan
IBM Certified MQSeries Specialist
MQSeries.net forum moderator |
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| jefflowrey |
| Posted: Tue Mar 16, 2004 9:59 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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In general, MQSeries channels are incompatible with IP based load-balancers.
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| jrjoe |
| Posted: Wed Mar 17, 2004 7:22 am Post subject: |
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Acolyte
Joined: 20 Jan 2003
Posts: 60
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Thanks for the info regarding this. What are my options as far as hardware failover (cheapest at this point).
I know that HACMP is one.
Thanks again
Joe |
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| MQKev |
| Posted: Tue Aug 15, 2006 5:31 am Post subject: |
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Newbie
Joined: 07 Nov 2005
Posts: 9
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| jefflowrey wrote: |
| In general, MQSeries channels are incompatible with IP based load-balancers. |
Hi,
we have a similar problem. Do you know about MQClients and IP based load-balancer?
We (try to) use a Cisco Content Switch for clustering two identical Queue Managers (V5.3 // AIX 5.3), Client is a Server Application on Win2k. This Client is not able to connect via channeltab, so i couldn't use MQClustering (for HA) 
MQ is able to keep connections to Queue Managers which aren't in "load-balancing-range" any more, thats a problem. The network guys say, thats impossible  . Any experience out there?
greetz Kev |
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| jefflowrey |
| Posted: Tue Aug 15, 2006 5:35 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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MarkT has informed me that client channels work just fine with load-balancers.
MQ Clustering wouldn't have given you HA for a client app, anyway.
Or, really, HA for anything else.
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| MQKev |
| Posted: Wed Aug 16, 2006 5:07 am Post subject: |
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Newbie
Joined: 07 Nov 2005
Posts: 9
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| jefflowrey wrote: |
MarkT has informed me that client channels work just fine with load-balancers.
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That sounds great. But my Clients continue polling (getWait(30)) my backup Queue Manager while the primary machine returns in active status an the virtual IP of the Content Switch does route exclusively to this primary Box? 
Is MQ able to remember a IP beyond the virtual IP?
(In the case of a switch to the backup system there are - as intended - TCP/IP-Errors in my AMQERR01.LOG. MQ talks about the virtual IP)
greetz Kev  |
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| jefflowrey |
| Posted: Wed Aug 16, 2006 5:14 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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If the client is in an get/wait, it might not notice that the channel has gone away and needs to be reconnected. It depends a bit on things like KeepAlive and heartbeats.
What happens if you restart your client apps? And, to be clear, it works fine when you fail to the backup but not when you fail back to the primary? Or it doesn't work when you fail to the backup?
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| MQKev |
| Posted: Wed Aug 16, 2006 5:42 am Post subject: |
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Newbie
Joined: 07 Nov 2005
Posts: 9
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If my primary System gets down, the switch does route everything to the backup without any problems. But of course, that works because my Clients will reconnect due to the errors of the broken primary system. Thats ok for me, i just need a fast switch in the case of a not-working primary system.
But after my emergency switch the primary Queue Manager will return to work (i hope so^^), and then the content switch routes to the first box, but my clients stay on the backup one.
This leads to two more problems: Other Clients (the "real" client) put their requests to the primary one, while the Server Application still polls the backup Queue Manager.
The other problem is, that Win2k may crash in this case and needs to be rebooted with the "Power"-button But thats not the point, could be anything else.
KeepAlive and Heartbeat is a very good tip, thanks. I will search for a solution that way 
thx & greetz Kev |
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| jefflowrey |
| Posted: Wed Aug 16, 2006 5:55 am Post subject: |
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Grand Poobah
Joined: 16 Oct 2002
Posts: 19981
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If the primary crashes, then the connections get interrupted and then your client apps reconnect.
If the primary comes back up, but the backup doesn't go down, then the connections won't get interrupted and your client apps won't reconnect.
The switchover of the virtual ip does not affect existing connections.
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