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Hi Horms,
On Fri, 28 Jun 2002, Horms wrote:
>
> Interestingly I note that if a backup linux director takes over a
> connection, its connection counters are not updated accordingly.
Yes, the synchronized connections don't affect the server connection
counters. After the backup takes over, new connections can be recorded in
the server connection counters. And, in the most cases, the synchronized
connections expires soon, so it doesn't affect the load balancing among
the servers too much.
> This is not a big problem, and doesn't cause any negative counts to
> crop up, but may be worth fixing at some stage. What are your
> thoughts?
>
There are several reasons that synchronized connections are not used in
the server connection counters.
1) In many HA implementation, the backup load balancer doesn't have the
ipvs scheduling table when it is in the standby mode. So, when the backup
receives the synchronized connections, there is no server entry to update
connection counters.
2) Even if the backup load balancer has the ipvs scheduling table, it is
hard to lookup its server entry (through the address and port numbers).
For example, you have to look up the virtual service first, if the
connection belongs to the fwmark-based services, it is not possible to get
the service entry through address and port. Then, you will have to
synchronize the connections with its service info, it will transfer more
data and bring more overhead.
3) Keep it simple :)
Regards,
Wensong
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