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rsacheen
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Apr 25, 2017

ratio(member) and persistence profile

BIG-IP LTM 800 (Ver. 11.5.3)

 

ratio(member) load balancing method I set for my pool doesn't seem to work as expected. I have 10 pool members. I set the ratio of one member to 5 and set ratio value 10 for remaining 9 members. connections aren't distributed evenly across the 9 node members though they have equal ratio value. One of the node member gets overloaded.

 

I found a similar case like mine on the internet.

 

http://h20564.www2.hpe.com/hpsc/doc/public/display?docId=mmr_sf-EN_US000005176

 

Looks like, the persistence profile I have set for my VS is causing trouble. But don't know why. I also don't have any clue as to why [Ignore persisted weight] option isn't working. The article says,

 

when a static load balancing method such as Round Robin is used along with a BIG-IP configuration object that affects load distribution, such as a OneConnect >profile or a persistence profile, traffic may not be evenly distributed across BIG-IP pool members as expected.

 

Well, I am using static load balancing method (ratio) and I have persistence profile set as well. I cannot disable/delete the persistence profile due to some technical constraints. I don't know what can be the solution in my case. I don't know why ratio load balancing can be “skewed” due to the existence of this persistence entry while round-robin works perfectly well with the same persistence profile.

 

2 Replies

  • What kind of persistence profile are you utilizing ? Are you using OneConnect ? Any netmask being utilized in either persistence profile or OneConnect ?

     

  • Hi,

     

    You should understand that persistence overrides LB decisions. Something like that:

     

    First packet (no persistence record found) - new connection, LB method used to choose member Next packet (persistence record exist) - no LB, packet send to member defined in persistence record.

     

    Because SIP persistence can be configured to use specific header in SIP message then maybe header used is repeated in many SIP messages, so most of the packets are directed to the same member for which persistence record already exists.

     

    Piotr