Forum Discussion

Ecesureshkumar's avatar
Ecesureshkumar
Icon for Nimbostratus rankNimbostratus
Aug 13, 2015

Source Address Persistence Issue - sometime Load Forwarded to single APP server while application restarts

Hi there,

 

We have three Web servers and two Application servers and have persistence configuration for application functionality.

 

VS_WEB – Cookie Persistence VS_APP – Source Address Persistence

 

ISSUE:- Sometimes cases, while we restart Web/APP server, we need to clear persistence then only Load sharing happening else load is forwarded to only one APP server which restarted first. But at web layer load is share equally.

 

Can anyone suggest solution to overcome this issue, or help us in creating irule for our setup.

 

I would appreciate your valuable response on this. Please do revert if any more details required on this.

 

application delivery
availability
deployment
devops
iRules
LTM

3 Replies

Sort By
  • Christophe_Lem2's avatar
    Christophe_Lem2
    Icon for Cirrus rankCirrus
    Aug 14, 2015

    When you restart your app servers, one will be available first. If you have permanent traffic between your web servers and VS_APP, the persistence record will never expire and therefore the first app server will keep all the load.

     

    If you don't want that behaviour, you could use cookie persistence towards the app servers as well.

     

    • Ecesureshkumar's avatar
      Ecesureshkumar
      Icon for Nimbostratus rankNimbostratus
      Aug 25, 2015
      instead of cookie persistence, can we check on irule to for Web1 to APP1 (fallback App2) and similarly Web2 to APP2 (fallback APP1). Can you help us to create this irule
  • Kevin_Stewart's avatar
    Kevin_Stewart
    Icon for Employee rankEmployee
    Aug 25, 2015

    So how do you have this put together now? Is it a single client side VIP with 3 web servers in a pool, and those three web servers point to a separate VIP that has 2 app servers in a pool? And if so, how do you intend to distribute traffic to the app servers since there's an uneven ratio?