Failover and pools with single machines
dhcp1 at thehobsons.co.uk
Fri Dec 15 15:29:04 UTC 2006
Tina Siegenthaler wrote:
> > On the other hand, with non-failover (independent)
> > pools, as
>> Simon suggested, the lease files can more often hold differing
>> information: one
>> lease file showing the address assignment while the other does not.
>The setup has now been running for ten minutes, and it seems that the
>leases are logged identically on both servers, even the "fixed" ones.
>But it's only ten minutes... I'll have to check again on Monday and
>compare the logs and lease files.
The leases files will NOT be the same.
What will happen is that both servers will respond to a broadcast
discover, and enter a lease into their database with a life of 2
minutes. The client will then request the lease from ONE of the
servers and that server will enter a new lease entry with the real
expiry time. The server that didn't get to hand out the full lease
will expire it's offer after two minutes and mark the address as free.
So when you analyse the leases to see what's active etc, you need to
aggregate the leases files from both servers and look only at the
latest leases. IFF you analysis program looks at the timestamp for
the lease entries and correctly ignores ones that are earlier than
it's already found, then you may be able to get away with
concatenating the leases files from both servers and analysing the
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