failover, partner-down state, MCLT and rewind binding

Simon Hobson dhcp1 at
Tue Nov 10 10:27:49 UTC 2015

Gregory Sloop <gregs at> wrote:

> Fairly quickly, got the secondary back up.
> It handled all it's assigned leases fine, as far as I can tell. It then handed out all the remaining pool leases it had. Then it ran out of leases.
> I expected it to start recovering the leases from the peer [primary] at this point, and extend [rewind] the leases the primary had already issued.
> While I'm not sure how the "rewind" provision worked - we were getting "peer holds all free leases" messages for quite a while.
> I didn't think this should be happening - but then I looked at the MCLT time and it was set to 1800 [30m]

It is not clear, did you set that server into "partner down" mode ?

If not, then AIUI what you saw was normal.

What you need to do in these situations it to manually set the surviving server into partner down mode - then it can have free use of the entire range and will "just work" as though it's a single server. When the peer comes back up, then they should automatically return to normal mode.

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