On Sat, 1 Nov 2008, Robinson, Eric wrote:
> I changed it to 5 seconds, but no significant change was apparent. Then
> I changed it to 10 seconds and there was a definite, observable drop in
> CPU utilization. A graph of the past 6 hours shows that usage has now
> flattened out and is now averaging less than 10%.
In the early days of LVS, all failover was set to at least
30secs as the tcpip stack is designed to tolerate somewhere
between 30-90sec (depending on the OS) of lost packets (if
routing goes down) before sending back icmp errors to the
sending node. On that understanding, all applications can
expect silence on that time scale before the routing
underneath rearranges itself.
For the number of times you have a forced failover of a
realserver (once every couple of months at most), I can't
imagine that doctors will notice. Planned downtime will
involve setting the weight to 0 and then shutting down the
node, when all connections are dropped
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
generator at http://www.wm7d.net/azproj.shtml
Homepage http://www.austintek.com/ It's GNU/Linux!