CSM Real server failover delay

[Muhammad Anser Khan]

Dear All

We are facing an issue with a cisco CSM Load Balancer Module running version 3.1(4).

The scenario is that we have two IBM WebSphere Application Servers that we are trying to load balance using CSM. During perfromance testing, the systems team tried to simulate 50 simulaneous users to the Load Balanced VIP IP (10.10.10.1) on port 443. When both real servers are UP and running, we saw the connections were equally distributed among the two real servers (10.10.10.2 and .3).

However when they shut down one of the real servers NIC, we see that CSM marks the server as operationally down (displaying PROBE_FAILED status). But as soon as one of the real server fails, the CSM stops all requests for the virtual server, and the client application shows that no requests are reaching any of the real servers for about 10 seconds. After this period normal connections are established with ONE Active Real Server. We thought that if one real server goes, at least half of the connections should still continue to work.

Please see attached graph for more information. What could be the reason for this issue? Below is the relevant configuration:

probe ICMP icmp

interval 2

retries 3

failed 3

receive 10

!

serverfarm Server-Real

nat server

no nat client

real 10.10.10.2

inservice

real 10.10.10.3

inservice

probe ICMP

!

vserver Server-LB

virtual 10.10.10.1 tcp https

serverfarm Server-Real

no persistent rebalance

inservice

Regards

Anser Khan

[Muhammad Anser Khan]

Dear Gilles,

Can we try to upgrade the CSM software to 3.1(x) or 4.1(x) instead of upgrading directly 4.2(12) from 3.1(4).

What do you advice?

Regards,

Anser

[Gilles Dufour]

try to go the latest 3.1.x and from there to the first 4.1.x and then from there to 4.2.x

Gilles.

[yessercco]

Dear Gilles,

We console the CSM module and following are the logs we are getting:

Laminar v1.0

Starting SDRAM Data bus test... COMPLETE!

Starting SDRAM Address bus test... COMPLETE!

Starting SDRAM Fill test ... SDRAM Complement Fill Test FAILS!

Address 0053A5B0 contains FEAC5A4F Expected FFAC5A4F

*** PPC FAILS SDRAM TEST! SYSTEM HALTED ***

Laminar v1.0

Starting SDRAM Data bus test...

COMPLETE!

Starting SDRAM Address bus test... COMPLETE!

Starting SDRAM Fill test ... SDRAM Complement Fill Test FAILS!

Address 0053A5B0 contains FEAC5A4F Expected FFAC5A4F

*** PPC FAILS SDRAM TEST! SYSTEM HALTED ***

and so on....

It seems to be H/W SDRAM issue.

Should we open the TAC case or directly open the RMA.

Please suggest.

Regards,

Anser

[Muhammad Anser Khan]

Reminder !!!