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Re: OpenLDAP 2.4.15 : CSN too old when using 4-way multimaster

Le vendredi 27 février 2009 18:37:33, Quanah Gibson-Mount a écrit :
> --On Friday, February 27, 2009 3:43 PM +0100 Adrien Futschik
> <adrien.futschik@atosorigin.com> wrote:
> > Hello everyone,
> >
> > I also have to say that if I stop M3 & M4 and try to add entries to M1 &
> > M2, I  don't get the "CSN too old" messages and all entries a replicated
> > correctly  !!!
> >
> > Is this because Multimaster is limited to 2-3 instances ? The reason why
> > I am  trying to build a 4-way master architecture is because I would like
> > to be able  to stop one server and perform a slapcat, even if one
> > "physical" server is  down...
> N-Way means for any value of N.  So 4 should work just fine.  Are all 4 of
> your servers tightly synchronized, time-wise?  I.e., using ntp to make sure
> their clocks all agree?
> --Quanah
> --
> Quanah Gibson-Mount
> Principal Software Engineer
> Zimbra, Inc
> --------------------
> Zimbra ::  the leader in open source messaging and collaboration

Considering that M1 & M3 are on the same server and therefore have exactly the 
same time, if this was a time related problem, I should'nt get any "CSN too 
old" messages between M1&M3 and M2&M4, should I ?

I have also noticed that when M1 gets a new entry and passes it to M2&M3&M4, 
when M2&M3&M4 revieve it, they also pass it to M2&M3&M4 ! I don't understand 
why this happends but it look's very much like this is what's happening, 
because sometimes, M2 would have passed-it to M4, before M4 has actualy 
revieved the add order from M1.

I therefore happend to notice that sometimes, entries send from M1 are 
revieved in the wrong ordrer by other masters and therefore some entries may 
be skipped !!!

Here is a example :
I add cn=M1client1 & cn=M1client2 on M1, 

M1client1 & M1client2 are successuly replicated on M2&M4 but on M3, only 
M1client2 is inserted and I am getting an "CSN too old" message for M1client1 
on M3.

I don't have the logfile here, I'll send extracts this monday.
I am also getting this messages from time to time :
=> bdb_idl_insert_key: c_put id failed: DB_LOCK_DEADLOCK: Locker killed to 
resolve a deadlock (-30994)
=> bdb_dn2id_add 0x1e40: parent (ou=clients,o=edf,c=fr) insert failed: -30994

I guess this is because all 4 masters recieve entries that have the same 
parent : ou=clients,o=edf,c=fr and that happends if two entries are "inserted" 


Adrien Futschik