Why is load balancing not working in my indexer cluster with my current tcpout stanza in outputs.conf?

[ckillg]

Only indexer 4 appears to be receiving data. Outputs.conf below.

[tcpout]
defaultGroup = default-autolb-group

[tcpout:default-autolb-group]
server = shv-ms-splunki1:9997
server = shv-ms-splunki2:9997
server = shv-ms-splunki3:9997
server = shv-ms-splunki4:9997

[yannK]

The correct form is to put all the destination servers in the same list.

 [tcpout:default-autolb-group]
 server = shv-ms-splunki1:9997, shv-ms-splunki2:9999, shv-ms-splunki3:9997, shv-ms-splunki4:9997