Forum Discussion
NimbostratusNewbie question about LTM load balancing
Hi,
We currently have pools and nodes configured as follows, where there is one primary server and one secondary server.
The resulting load balancing algorithm is only really achieving a failover, where the primary server is always used, unless that has a problem, in which case the secondary server is used instead:
ltm node /Common/primary {
address PR.IM.IP.186
description "Server name is primary server"
ratio 65535
ltm node /Common/secondary {
address SE.CO.IP.186
description "Server name is secondary server"
ltm pool /Common/service_Pool {
load-balancing-mode ratio-node
members {
/Common/primary:80 {
address PR.IM.IP.186
priority-group 1
}
/Common/secondary:80 {
address SE.CO.IP.186
priority-group 2
}
}
min-active-members 1
monitor /Common/http
Please could someone advise me on how to have a number of primary servers and a number of secondary secondary servers.
In F5 config language, I am looking for the below, but don't know what to set the ratio & priority-group numbers to and also if I need to have a different load-balancing-mode and min-active-members settings:
ltm node /Common/primary1 {
address PR.IM.IP.186
description "Server name is primary1 server"
ratio ????
ltm node /Common/primary2 {
address PR.IM.IP.187
description "Server name is primary2 server"
ratio ????
ltm node /Common/primary3 {
address PR.IM.IP.188
description "Server name is primary3 server"
ratio ????
ltm node /Common/secondary1 {
address SE.CO.IP.186
description "Server name is secondary1 server"
ratio ????
ltm node /Common/secondary2 {
address SE.CO.IP.187
description "Server name is secondary2 server"
ratio ????
ltm node /Common/secondary3 {
address SE.CO.IP.188
description "Server name is secondary3 server"
ratio ????
ltm pool /Common/service_Pool {
load-balancing-mode ratio-node
members {
/Common/primary1:80 {
address PR.IM.IP.186
priority-group ?
}
/Common/primary2:80 {
address PR.IM.IP.187
priority-group ?
}
/Common/primary3:80 {
address PR.IM.IP.188
priority-group ?
}
/Common/secondary1:80 {
address SE.CO.IP.186
priority-group ?
}
/Common/secondary2:80 {
address SE.CO.IP.187
priority-group ?
}
/Common/secondary3:80 {
address SE.CO.IP.188
priority-group ?
}
}
min-active-members 1
monitor /Common/http
Thanks in advance.
2 Replies
Ed_SummersYou can use the 'priority group' feature to accomplish having a "primary" and "secondary" group of servers. Simply have your "primary" servers in priority group 100 and secondary servers in priority group 50, for example. (Note that the priority groups are used in order of HIGHEST priority.) 'Min active members' determines when the next priority group of servers comes online to accept connections. Once the available members in priority group 100 falls below 'min active members', BigIP brings the next group online for connections. In your example, the servers in priority group 2 will be active first, then priority group 1 active should the 'min active members' in group 2 fall below the level you set. Some additional info is available at:
The 'ratio' setting is related to the load balancing method, and does not determine when priority groups are activated. It relates to the ratio of new connections each server in a pool will receive. A common example used for 'ratio' LB methods is servers having differing performance characteristics. Ratio can weight connections more heavily to some servers over others to allow more 'powerful' servers to get more connections. You have not indicated such a case in your description so I am not sure that a 'ratio' LB method is right for your environment. The round-robin LB method will work fine with priority groups if your servers have similar characteristics.
Hope this helps...?
- Rich_T_187288
Hi Ed,
Thanks very much for this, really helpful and will get me going.
Cheers,
Richard.
