Failover concept clarification

[David W. Hankins]

On Tue, Jul 07, 2009 at 04:49:54PM +0530, pat wrote:
> What will be the time to expire before my secondary responds to all the
> clients request?

Load balancing is only engaged in 'normal' state.  In all other
operating states, the server will always answer as best it can.

> is it 00hr:09min:41sec + 1800 sec = 00hr:39min:41sec so my secondary server
> will wait for 39min and 41 sec before answering all my clients request.
> 
> how do i calculate the STOS+MCLT time.

You got this right.  This time effectively determines when the
partner's free lease pool will be available for allocation to new
clients, although this is actually a case-by-case basis on each
individual lease.  The actual time is TSFP+MCLT or STOS+MCLT,
whichever is further in the future.  Generally free leases have a
TSFP that is in the past, so STOS+MCLT is the effective measure.

However, expired leases, or leases reaching expiry, may have a
TSFP that is still in the future (the TSFP lags ahead of lease
expiration so that leases may be extended to lease-times greater
than MCLT).

STOS+MCLT doesn't affect LBA.

-- 
David W. Hankins	"If you don't do it right the first time,
Software Engineer		     you'll just have to do it again."
Internet Systems Consortium, Inc.		-- Jack T. Hankins
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