Ian Cartwright wrote:
> On Fri, 2004-01-02 at 15:45, M. G. (Michael) de Bruin wrote:
>>Bart Smit wrote:
>>>Hi Manuel & lists (cc-ing -dev),
>>>>m0n0wall loses the DHCP lease database on reboot - this is a design
>>>After actually digging up and reading the relevant RFC (2131), I feel
>>>the need to reiterate my previously stated point that this is a bad
>>>design choice. It conflicts with an explicit design goal of the DHCP
>>>mechanism. To quote:
>>> > The following list gives design goals specific to the transmission of
>>> > the network layer parameters. DHCP must:
>>> > o Retain DHCP client configuration across server reboots, and,
>>> > whenever possible, a DHCP client should be assigned the same
>>> > configuration parameters despite restarts of the DHCP mechanism,
>>>I really feel this leaves no room for slack (apart from the fact that
>>>I'm one of those rare folks that is actually bitten by the loss of state) .
>>>Will a big "please" do? :-)
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>>I think you are going to have added cost as soon as you implement this:
>>especially with a short lease time, your CF will wear out very soon.
>>But: is it possible to use an NFS mount for these kind of things? If you
>>really need it you probably don't mind setting up another server w/ NFS
>>(eh... am I the only geek with to many servers? :)). Or, is this too
>>Anyway, just a thought.
> Or, how about this: keep the dhcp.leases file in memory (probably in
> /var/etc, which is where it is kept today, I presume) and save it to
> flash whenever the system is rebooted (using the M0n0wall equivalent of
> rc.shutdown). This would save wear and tear on any CF while giving lease
> information across (graceful) reboots.
I think this would be another solution indeed. The great advantage is
you don't wear out your CF, the great disadvantage is that you only keep
it with a controlled reboot. Since I happen to know not everyone has 2kw
UPS (actually, I do, but I'm kind of crazy on those things :)), you
would have a problem with a power outage.
But, from what I can see, there could be three choices for three
situations (and depending on your needs):
- Just save it on the HD, if that's what you are using. HD setup doesn't
have a problem with write actions
- Save it in mem and write to CF at shutdown/reboot (saves your CF but
doesn't work at uncontrolled reboot)
- Save it on a safe location, for example an NFS server, if you are
worried your CF will wear out (maybe a bit too drastic, for something
non-mission critical - if you do need this, shouldn't you use a seperate
Darn, I just killed my idea, sort of...
How hard would that be to implement? (*looking at Manuel*)