Data Domain: MSG-REPL-00403: Warning “repl client sent an unexpected segment” During Replication

Summary: Replication may post a warning when an unexpected segment is received. If replication can continue, it does so automatically.

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Symptoms

Warning messages like the ones below may appear in autosupports from the source Data Domain: 
Recent Alerts and Log Messages
------------------------------
Sep 27 04:54:40 DataDomain-Hostname ddfs[24044]: WARNING: MSG-REPL-00403: repl ctx 1:30: server error in send_segs: repl client sent an unexpected segment.
Sep 27 12:50:01 DataDomain-Hostname  ddfs[24044]: WARNING: MSG-REPL-00403: repl ctx 1:5: server error in send_segs: repl client sent an unexpected segment.
 
On the source system in /ddr/var/log/debug/ddfs.info: 
repl ctx 1:2: mrepl_send_file: failed to communicate with destination, error code 4 (RPC: Unable to receive) send_queue_send_data[8530]: data transfer done (failed to communicate with destination, error code 4 (RPC: Unable to receive))
 
On the target system in /ddr/var/log/debug/ddfs.info: 
WARNING: MSG-REPL-00403: repl ctx 1:30: server error in send_segs: repl client sent an unexpected segment

Cause

This warning occurs when replication receives an unexpected or out‑of‑order segment due to:

  • Network congestion
  • Transient connectivity loss
  • Intermittent packet drops
  • Temporary communication disruption between source and target

It does not indicate a replication software defect.

Resolution

1. Verify Network Health

Ask the customer’s network team to check the network for:

  • Packet drops
  • High latency
  • Routing instability
  • WAN congestion

Validation should focus on the timeframe when the warning occurred.

2. Check Replication Status

If replication is synchronized and resumes automatically:

  • The warning can be safely ignored
  • No Data Domain issue is present

Replication will retry and continue normally once connectivity is restored.

3. If Warnings Persist

If the warning does not clear or replication remains unsynchronized:

  • Investigate persistent network issues
  • Review link reliability between systems
  • Collect support logs for further analysis

Affected Products

Data Domain
Article Properties
Article Number: 000203824
Article Type: Solution
Last Modified: 16 مارس 2026
Version:  2
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