[Freeipa-users] changing the default for changelog trimmimg

[Petr Spacek]

On 3.7.2015 14:21, thierry bordaz wrote:
> On 07/03/2015 02:03 PM, Petr Spacek wrote:
>> On 3.7.2015 11:45, thierry bordaz wrote:
>>> On 06/30/2015 03:54 PM, Ludwig Krispenz wrote:
>>>> Hi,
>>>>
>>>> 389-ds allows to configure the max size of the replication changelog either
>>>> by setting a maximum record number or a maximum age of changes.
>>>> freeIPA does not use this setting. In the context of ticket
>>>> https://fedorahosted.org/freeipa/ticket/5086 we are discussing to change the
>>>> default to
>>>> enable changelog trimming.
>>>>
>>>> Does anyone already use changlog trimming or is there a  scenario where you
>>>> rely on all changes being available ?
>>>>
>>>> Thanks for your feedback,
>>>> Ludwig
>>>>
>>> Hello,
>>>
>>>     I think it is reasonable to set nsds5ReplicaPurgeDelay and
>>>     nsslapd-changelogmaxage to similar value.
>>>
>>>     When a replica (master or consumer) is down for some time and is
>>>     restarted, both attribute express the ability to get the replica in
>>>     sync with the rest of the topology.
>>>     It can work (and likely will) if
>>>     nsds5ReplicaPurgeDelay<nsslapd-changelogmaxage but there are always
>>>     corner cases that can lead to problem (like entries that diverge).
>>>
>>>     Currently purgedelay=7days (default) and changelogmaxage is infinite
>>>     and changing purgedelay=infinite impacts the size of the entries.
>> I wonder if these values could/should be controlled by topology plugin. Does
>> it make sense to have different values on different replicas?
>>
> Purgedelay can be different on each replica but it makes sense that the value
> is the same on all replicas. It is used to remove too old csn and so how far
> in the past the replication can decide which value is more recent than an
> other one. With different values of purge delay, a replica can decide to keep
> one value and an other replica can decide the opposite.
> Currently purgedelay is identical on all replicas (default value).

I understand that technically it is possible so the question is more like
'does it even make sense'? Do we want to support it?

-- 
Petr^2 Spacek