DHCP pair messed up, second one only running cant get primary up.
Drew Derbyshire
swhobbit at derbyshire.us
Mon Jan 16 22:01:03 UTC 2017
On 1/16/17 11:48 AM, Bob Harold wrote:
>
> On Mon, Jan 16, 2017 at 12:14 PM, Drew Derbyshire
> <swhobbit at derbyshire.us <mailto:swhobbit at derbyshire.us>> wrote:
>
> As an aside ...
>
> The thought of putting recovery state/log files (i.e. the DHCP
> leases file and its backup) on a RAM disk to make top look pretty
> leaves me dismayed. That leaves zero local protection against a
> system crash (or misguided deliberate reboot).
>
> And yes, the server has been running 346 days -- Doesn't matter.
> Services can be five nines reliable, but hardware won't be.
>
> An SSD, or if you prefer multiple SSD units configured as a raid,
> will give you the same order of performance without the premortem
> fodder.
>
> The machine should be audited for other critical files which are
> written to volatile storage, and moved to the SSD or other storage
> as well.
>
> -ahd-
>
>
> I agree that putting state in ram is a concern, but with a failover
> pair, there should be a duplicate copy on the other server of all but
> the very latest changes. There is a risk when one server is rebooting,
> so having a copy of the backup lease file on real disk would help.
> I think SSD (particularly write speed) is still orders of magnitude
> slower than ram.
>
> That said, I would not ever want to have both servers rebooted at the
> same time, or even restart DHCP at the same time. Restart one, allow
> it to sync data and get to normal-normal, then restart the other.
>
I would suggest the performance difference between RAM and SSD is
meaningless to the client. But the whole environment (like how much
traffic the one DHCP server is handling) has a subtle strangeness about
it which makes me nervous.
But Not my servers. Not my pager going off.
Good to hear both servers are back online. We'll leave it at that.
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