Symantec Directory : Bi-directional replication problem.

Products

• CA Directory

Issue/Introduction

In an environment with multiple hosts with DSAs setup for bi-directional MW-DISP recovery replication, there may be a situation where replication does not work as expected.  To make it simple, following scenario describes a situation with two hosts.

e.g. Host1 has 'DSA1' and Host2 has 'DSA2'.

Observation would be that replication from Host1/DSA1 to Host2/DSA2 is working as expected while not the other way around. In other words, the replication works only in one direction.

Following warnings/errors are seen in DSA2 (on Host2) log:

[7] 20240108.080742.682 DSA_E2735 Multiwrite-DISP: Unable to synchronize with peer 'DSA1'

Along with... 

[64] 20240108.010446.178 WARN : Attempting to send update to peer DSA1'
[7] 20240108.010446.179 WARN : comms_recv: No route to host
[64] 20240108.010500.160 WARN : updateIdleLastUpdateTime: DSA1: 4
[64] 20240108.010547.188 WARN : MW-DISP not in sync for 'DSA1'

Resolution

The most common problem is related to either OS or network settings. The key here is "WARN : comms_recv: No route to host". This 'no route to host' is in reference to the fact that Host2/DSA2 in above example is not able to find it's path towards Host1/DSA1 to apply the replication changes. Recommendation is to work with your OS Administrator team and/or your network team to find out what is misconfigured or missing.

e.g. If on Linux, start with /etc/hosts file on hosts to confirm all is good and take it further from there (i.e. firewall rules etc.)