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Re: Denying access to syncrepl consumere during initial DIT content load



Howard Chu wrote:
> Michael Ströder wrote:
>> Howard Chu wrote:
>>> Michael Ströder wrote:
>>>> Howard Chu wrote:
>>>>> Christian Kratzer wrote:
>>>>>>
>>>>>> I remember a discussion some time ago about the possibility of delaying
>>>>> access to a syncrepl. consumer during the intial DIT load.
>>>>>
>>>>> http://www.openldap.org/lists/openldap-bugs/201308/msg00043.html
>>>>>
>>>>> Feel free to experiment with it and see whether it suits your need.
>>>>
>>>> Why was this undocumented strictrefresh option limited to delta-syncrepl?
>>>
>>> Just expedient at the time, it would take more code to cover other cases. Also
>>> it wasn't clear to me that this was actually a good approach, thus the need
>>> for other developers to test it and give feedback.
>>
>> Hmm, it's some work and risk to change a serious setup to delta-syncrepl.
>>
>>> The biggest problem with this approach is that it has global impact - turning
>>> off slapd's listeners. On a slapd with multiple independent databases, this
>>> would be a bad idea.
>>
>> IMO that's not really an issue because
>> 1. you likely have many replicas serving the same set of databases to
>> clients and
>> 2. it's very likely that you're initializing all DBs at once because if
>> deploying a new server, recovering after file system corruption etc.
> 
> An obvious counter-example: a server with multiple databases, consuming from
> distinct providers. If the connection to one of those providers is lost and
> reconnected, the current code would disable slapd globally but only one of the
> multiple DBs needs to be blocked.

If you have HA requirements in such a replication setup you will set up
another replica with such a configuration => see "set of databases" in item 1.
above.

>> Anyway having an slapd-internal mechanism is way better than external
>> work-arounds with monitoring contextCSN and using iptables etc.
> 
> Sure. But again, it requires more thinking, there are plenty of undesirable
> side-effects to any approach you can mention.

Thinking is always good.

Ciao, Michael.

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