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Cisco ACE back up real server failover

lwlim8888
Level 1
Level 1

Hi,

I'd like to find out if its possible with this scenario. When a real server had failed, and the assigned backup-server is then serving the traffic, but when the failed real server came back online, I want the backup server to continue serving traffic and not the recovered real server.

I have not found a way to achieve this and want to confirm it's possibility.

Thank you

1 Accepted Solution

Accepted Solutions

Hi,

It's possible but manual intervention is required. So when real server goes down and backup takes over, you can make the down server as the backup one and this backup one as the regular one. But if you leave everything as it is, then as per the default behavior(which cannot be changed), the backup server will server the traffic as long as regular real is down, once that comes up, new connections would be sent to it and existing connections would be continued to be served by backup real.

Regards,

Kanwal

View solution in original post

10 Replies 10

Kanwaljeet Singh
Cisco Employee
Cisco Employee

Hi,

This is the default behavior. The existing connections will continue with the backup server and only "NEW" connections would be sent to the other real which has come back "operational". If you don't want any connections at all on the "operational" real server, then there is no way possible. You will have to make changes manually.

Regards,

Kanwal

 

 

 

Hi Kanwal,

 

Thank you for your reply.

Actually I want the back up real server to continue serving for new and existing traffic, and not the real server that have recovered from failure. Is this possible?

Regards

Hi,

It's possible but manual intervention is required. So when real server goes down and backup takes over, you can make the down server as the backup one and this backup one as the regular one. But if you leave everything as it is, then as per the default behavior(which cannot be changed), the backup server will server the traffic as long as regular real is down, once that comes up, new connections would be sent to it and existing connections would be continued to be served by backup real.

Regards,

Kanwal

Hi Kanwal,

Thank you again for your reply, that cleared my doubt.

Regards

axfalk
Level 1
Level 1

There's a limit of 3 chained backup servers in A5(1.0)  and I can't find any documentation on the limit on the number of chained backup servers in A5(2.1), which is what we're running.

Does anyone happen to know what that limit is?

 

thanks.

 

Greg

 

 

 

 

 

Hi Greg,

The limit should be same. If nothing is reflected in release notes regarding the change, then it should be same.

Regards,

Kanwal

Thanks for the response. We have only one backup server that we're planning on using in conjunction with the 3 rservers that are currently part of the serverfarm, as per the following:

serverfarm host SV

  predictor leastconns

  probe SERVER_80

  rserver SERVER01 80

    backup-rserver BACKUP

    inservice

  rserver SERVER02 80

    backup-rserver BACKUP

    inservice

  rserver SERVER03 80

    backup-rserver BACKUP

    inservice

  rserver SERVER04 80

    backup-rserver BACKUP

    inservice

  rserver backup-rserver BACKUP

   inservice standby

 

Does the 3 backup server limit apply to this as well?

 

thanks again..

 

_ Greg

Hi Greg,

serverfarm host R1
  rserver R1
    backup-rserver R1B
  rserver R1B
    inservice standby
  rserver R2
    backup-rserver R1B
    inservice
  rserver R3
    backup-rserver R1B
    inservice
  rserver R4
    backup-rserver R1B
    inservice
  rserver R5
    backup-rserver R1B
    inservice


It doesn't seem that limit applies the way you want to configure. As you can see above i added the same rserver as backup rserver for more than 3 reals. So the limit should be not more than 3 DIFFERENT BACKUP rservers.

 

Regards,

Kanwal

appreciate the response...thnx a lot...

 

Greg

Hi Greg,

No problem. Happy to help!

Regards,

Kanwal

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