Antw: Re: Replication issues with delta-syncrepl, MMR and memberOf overlay on 2.4.47

["Ulrich Windl" <Ulrich.Windl@rz.uni-regensburg.de>]

>>> Mark Cairney <Mark.Cairney@ed.ac.uk> schrieb am 06.06.2019 um 13:12 in
Nachricht <c2ecf5a2-94bc-3ff0-75df-8142da2944a8@ed.ac.uk>:
> Hi Quanah,
> 
> 
> On 05/06/2019 19:09, Quanah Gibson-Mount wrote:
>> --On Wednesday, June 05, 2019 11:38 AM +0100 Mark Cairney
>> <Mark.Cairney@ed.ac.uk> wrote:
>> 
>>> Hi,
>>>
>>> We currently run a multi-master setup where all 4 of our servers
>>> replicate from each other via delta-syncrepl but all our writes are
>>> directed at a selected "master" server.
>>>
>>> I've noticed recently that we are suffering sync issues and this
>>> coincides with us upgrading from 2.4.46 with a patch for ITS8843 to
>>> 2.4.47.
>> 
>> Hi Mark,
>> 
>> Error 0x14 would be attribute type or value already exists.  This would
>> indicate a fundamental problem of there being discrepencies between your
>> servers.  I.e., your databases are out of sync.
> 
> That smells a little bit like NTP sync but these boxes are all set to
> aggressively poll a single NTP server:
> 
> server 129.215.205.191  minpoll 4 maxpoll 6
> restrict 129.215.205.191 nomodify notrap
> 

You know that you should have preferrably four servers? If you have only one, I's suggest so configure peering amng your MMR masters; if the server fails, it's likely that at least the MMR masters agree on what time it is...

And if you seem in a hurry with time sync, maybe add "iburst" option as well...

[...]

Regards,
Ulrich