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student1_121897
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Jun 27, 2013

What is the impact of activating Connection Mirroring?

Hello,

 

I would like to know what should I expect (in terms of CPU usage, memory usage, delay, etc) if I activate Connection Mirroring on a redundant pair of LTMs?

 

I don't have a test environment and I wouldn't risk activating it without knowing more about consequences.

 

Thank you in advance.

 

Mihai

 

 

3 Replies

  • I understand the impact varies significantly depending upon specific configurations but when we activated connection mirroring for non-HTTP connections there was no observable impact on single-bladed Viprion. Peaking at about 1Gbps mirrored. From my readings this is unusual and impact should be expected. All that traffic glides over your HA link so that could be problematic if it isn't dedicated/direct-link.

     

     

    Although not performance related, the iRule-fires-on-Standby issue still exists in 11.2.1 HF3. I see with 11.4 there is an iRule that allows awareness of Active/Standby so the rules can be told not to run on Standby.
  • Yes, L4 connection mirroring will have much lower impact than using connection mirroring on a VS with an HTTP or other L7 profile. With L7 mirroring every packet and the full payload needs to be sent to the peer unit. Wth L4 it should be just the connection open and close packets.

     

     

    sol13478: Overview of Connection and Persistence Mirroring (11.x)

     

    http://support.f5.com/kb/en-us/solutions/public/13000/400/sol13478.html

     

     

    Although not performance related, the iRule-fires-on-Standby issue still exists in 11.2.1 HF3. I see with 11.4 there is an iRule that allows awareness of Active/Standby so the rules can be told not to run on Standby.

     

     

    Yes, see the HS::status wiki page for details:

     

    https://devcentral.f5.com/wiki/iRules.HA__status.ashx

     

     

    Aaron

     

  • Pete, Aaron,

     

     

    Thank you for your reply.

     

    In brief, I understand that for L4 is barely noticeable.

     

    For L7 what should I expect, as percentage increase ? assuming we have a dedicated VLAN and cable between units ?

     

     

    Regards,

     

     

    Mihai