Disabling The Fast Link Health Check - Radware Alteon Application Manual

Alteon Application Switch Operating System Application Guide
Health Checking
Examples
A (1|2)&(3|4)
Real servers 1, 2, 3, and 4 are configured in group 1 and assigned to virtual service x in Virtual
Server 1. The boolean expression is used to calculate the status of a virtual service using group
1 based on the status of the real servers.
Virtual service x of Virtual Server 1 is marked UP if Real Servers 1 or 2 and Real Servers 3 or 4
are health checked successfully.
>> # /cfg/slb/group 1
>> Real server group 1# advhlth (1|2)&(3|4)
>> # /cfg/slb/virt 1/service x/group 1
>> Virtual Server 1 Service# apply
>> Virtual Server 1 Service# save
B (1&2)|(2&3)|(1&3)
Real servers 1, 2, and 3 are configured in Group 2 and assigned to virtual service x in Virtual
Server 1. The boolean expression is used to calculate the status of the virtual service using
Group 2 based on the status of the real servers.
Virtual service x of Virtual Server 1 is marked UP only if at least two of the real servers are
health checked successfully.
>> # /cfg/slb/group 2
>> Real server group 2# advhlth (1&2)|(2&3)|(1&3)
>> # /cfg/slb/virt 1/service x/group 2
>> Virtual Server 1 Service# apply
>> Virtual Server 1 Service# save

Disabling the Fast Link Health Check

By default, Alteon sets the real server as operationally down as soon as the physical connection to it
is down, without waiting for the health check to fail. This behavior may not be advantageous in
certain configurations in which a link may go down and then be quickly restored, such as in VPN load
balancing. By disabling this "fast health check" behavior, the real server will be marked as down
only after the configured health check interval, thus allowing the possibility of the server
re-establishing itself before the next health check.
To enable or disable fast link health checks
>> # /cfg/slb/real
506
<real-server-#> /adv/fasthc ena|dis
(Select the Real Server Group 1)
(Configure a boolean expression for
health check)
(Assign the Real Server Group 1)
(Apply the changes)
(Save the changes)
(Select the Real Server Group 2)
(Configure a boolean expression for
health check)
(Assign the Real Server Group 2)
(Apply the changes)
(Save the changes)
Document ID: RDWR-ALOS-V2900_AG1302