LSLB - External processor unavailable

[khatfield]

Many, many times we have issues where it states external processor unavailable and it appears only when under a load. (Such as the LSLB process is around 8-9% cpu utilization)

We have timeout settings set around 10, Keep Alive On, Smart Keep Alive Off.

Just can't figure it out but 503 errors randomly but becoming a real nuisance.

LSLB 1.6 / FreeBSD 7.1 32-bit

Server on the other end normally has less than 10-15 concurrent connections. Never any real load. It doesn't always appear to happen just to busy sites, just appears when LSLB gets busy. System dmesg shows no issues, we're far from running out of connections, memory, cpu, iowait is good.

Thanks

 

[mistwang]

LSLB uses a "Ping URL" to verify backend periodically, expecting a "200 OK" response. if it failed to connection backend server, or backend server timedout or return something other than "200 OK". LSLB will mark that backend server as "unavailable". LSLB will log the error in error log.

LSLB only give 503 when all backend servers are not reachable.

If LSLB and backend server is over WAN connection, there might be interim network problem.

So, go through error log for the period you getting 503 error, you may be able to find out what was happening. Should set log level to "INFO".