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New Member

CSM slow start not working or not slow enough

Here's the basic config:

-serverfarm A is configured with leastconns, default slow start timer (1).

-serverfarm A has 18 servers added to it.

-variable REAL_SLOW_START_ENABLE is at 3, the default.

-IOS version: 12.2(18)SXD5

-CSM OS version: 4.2(2)

Here's the problem:

-When taking a server out of service and putting it back in, the server ramps up to the average connections so fast that the server's CPU spikes and many times it fails.

-The connections go from 0 to ~500 (the average at the time) in about a minute or less.

What we've tried:

-Setting the REAL_SLOW_START_ENABLE variable to 1, 2, 5, 9, with no apparent difference in ramp up speed.

-Setting the slowstart timer for serverfarm A to 300 seconds, with no apparent difference in ramp up speed.

-We're aware of caveats CSCef76686 and CSCei37874, but changing the variable value to 2, 5, or 9 should have negated those.

Anyone have any thoughts? Thank you.

3 REPLIES
New Member

Re: CSM slow start not working or not slow enough

Brad,

This could be CSCei26434, workaround is to use roundrobin predictor. The bug is resolved in 4.2(2.6) so if you have that or later, its something else.

Peter

New Member

Re: CSM slow start not working or not slow enough

Actually we ran into that bug separately, and doing a "no in" and"in" is a workaround. But this issue is different, it's more dealing with how fast the servers are taking on new connections once they're put in service.

New Member

Re: CSM slow start not working or not slow enough

Brad,

There does not appear to be any other existing bug that matches this description, so I suggest you open a case with the TAC if you have not done so already.

Peter

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