There is another thread "MirrorMode and chaining - are slaves needed?" which has caused me some confusion about MirrorMode and N-Way Multi-Master Replication.
Is the difference between MirrorMode and N-Way Multi-Master the number of nodes? 2 nodes = Mirror Mode, 3+ nodes = Multi-Master? But both use the exact same configuration?
If this is the case the documentation does not make this clear at all and using the MirrorMode directive in N-Way Multi-Master is very confusing. Why not "MirrorMode On" OR "MultiMaster On" ??
Is there a way to use two nodes in N-Way Multi-Master replication?
Alan Evans wrote:
The key element of MirrorMode is that there is an external frontend that ensures that all writes are directed to a single server. Otherwise, there is no difference.
----- "Howard Chu" hyc@symas.com wrote:
Should I change the docs for MM? We do writes to a single server to guarantee writes correct? If they are both the same, should we rename MirrorMode to a different key word?
We don't use the server URI in the MM example, maybe that section should be totally re-written as it seems to be confusing users.
Thoughts?
Gavin Henry wrote:
Well, at least maybe some clarification, if a total re-write is too time consuming. If the difference between the two has nothing to do with the number of nodes involved, and only whether or not there's an external frontend, perhaps they would be more aptly titled "N-Way Multi-Master" and "Proxied N-Way Multi-Master". And, perhaps any emphasis on the number of nodes involved should be removed to avoid ambiguity?
Just my thoughts, hope it helps Gavin. Let me know if there's anything I can do to help.
Respectfully, Ryan
Ryan Steele wrote:
consuming. If the difference between the two
has nothing to do with the number of nodes involved, and only whether or not
there's an external frontend, perhaps they
would be more aptly titled "N-Way Multi-Master" and "Proxied N-Way
Multi-Master".
Absolutely not. The name MirrorMode was specifically chosen to avoid any association with the concept of multi-master. The purpose of MirrorMode is to guarantee single-master consistency while providing hot standby.
How I can install OpenLdap in MirrorMode,
with limited write operations - only at 1-st server, and 2-nd servers works in read/write mode only when 1-st down, without a load-balancer ?
HC> Absolutely not. The name MirrorMode was specifically chosen to avoid any HC> association with the concept of multi-master. The purpose of MirrorMode is to HC> guarantee single-master consistency while providing hot standby.
openldap-software@openldap.org
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Ryan Steele