The parameter virtual_server.lvs_sched
in keepalived.conf supports two options for which I can't find an explanation:
fo
and md
.
Does anyone know their meaning?
keepalivedlvs
The parameter virtual_server.lvs_sched
in keepalived.conf supports two options for which I can't find an explanation:
fo
and md
.
Does anyone know their meaning?
Best Answer
The values allowed for
virtual_server.lvs_sched
are names of IPVS (IP Virtual Server) schedulers. The keepalived man page mentionsrr|wrr|lc|wlc|lblc|sh|mh|dh|fo|ovf|lblcr|sed|nq
as supported names for schedulers, quite a bit more than the original IPVS documentation describes.I had to take a peek at the kernel sources to see what those newer schedulers are:
fo
is "Weighted Fail Over" - All other scheduling modules implement some form of load balancing, while this offers a simple failover solution. The weighted failover scheduling algorithm directs network connections to the server with the highest weight that is currently available.Source: https://patchwork.ozlabs.org/patch/390597/
mh
is "Maglev Hashing"The algorithm is detailed in: 3.4 Consistent Hashing
For completeness from the
ipvasdm
man page provides descriptions of the other schedulers: