On 07/03/2015 02:28 PM, Petr Spacek wrote:
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?
https://access.redhat.com/documentation/en-US/Red_Hat_Directory_Server/8.0/html/Configuration_and_Command_Reference/Configuration_Command_File_Reference-Replication_Attributes_under_cnreplica_cnsuffixName_cnmapping_tree_cnconfig-nsDS5ReplicaPurgeDelay.html
...
When setting this attribute, ensure that the purge delay is longer
than the longest replication cycle in the replication policy to
preserve enough information to resolve replication conflicts and to
prevent the copies of data stored in different servers from diverging.
The longest replication cycle is identical for all replicas, so it is a
recommendation to use the same value.
I admit it could be more clearly stated.
If one decides to go with different values and complains about entries
that diverge, support will likely lead him to this page.
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