Re: Troubleshooting synchronization

["Torsten Schlabach (Tascel eG)" <tschlabach@tascel.net>]

Hi Dieter!

> The answer is quite simple: do not use multimaster replication in a
> production environment. In most cases the requirement for multimaster
> replication is just based on poor directory design.

If this is a "do not use feature", for what reason has it been included
in the software, in the first place.

> Slapd in a synchronized environment is, with a few exceptions which
> have only been fixed recently, rock stable, I know of environments
> with up to 150 consumers.

When you say "synchronized", do you mean one master and n slaves?

When you say, the requirement for N-way multi-master is usually poor
directory design, I wonder if I am suffering from a misconception here,
i.e. mixing up N-way multi-master and mirror mode possibly.

What we want to achieve is a HA solution where *all* directory data is
stored on more than one physical machine. I know I can do that by having
a master and a slave. But then I would need to have a mechanism entirely
external to slapd that if the master fails I turn the slave into a
master and vice versa. (However this could be reliably achieved.)

So the idea for N-way multi-master was just: I can point the DNS entry
to whatever server in my cluster (possibly there may be more than two)
and it will be a writeable directory and I won't ever loose any
information I write into that LDAP cloud.

Regards,
Torsten


Dieter Kluenter schrieb:
> "Torsten Schlabach (Tascel eG)" <tschlabach@tascel.net> writes:
> 
>> Hi Quanah!
>>
>>> I suggest you go read the CHANGES log for what has been fixed between
>>> 2.4.11 and the latest stable 2.4.19.
>> I need to say, it worries me a bit that for problems with a core feature
>> which has been around for quite some time, the answer is more often that
>> I like to hear: You need to use the latest version released last week /
>> month or so.
>>
>> I have indeed read the CHANGES and seen that some issues have been
>> fixed. I have no idea if we are affected by those issues or now.
>>
>> Also how would I know that *now* in 2.4.19 all problems are fixed and
>> the answer next week won't be: You need to use 2.4.20.
>>
>> But as this is a FOSS project and not a product we pay for, we
>> understand that we should not blame people but try and help if we find a
>> a problem.
>>
>> For that reason I have asked in my email for help on *understanding* and
>> *diagnosing* problems to have a chance to contribute in case we will
>> find any new issues.
>>
>> Also our customers may not like it if in case of a problem we tell them:
>> Let's wait if in some weeks a new release will come which will fix it or
>> not. So I'd rather be in a position to get my hands dirty myself in case
>> of problems.
> 
> The answer is quite simple: do not use multimaster replication in a
> production environment. In most cases the requirement for multimaster
> replication is just based on poor directory design. 
> Slapd as a stand alone directory is rock stable and outperforms all
> other products I know of.
> Slapd in a synchronized environment is, with a few exceptions which
> have only been fixed recently, rock stable, I know of environments
> with up to 150 consumers.
> 
> -Dieter
>