Netapp NDMP error communicating with tape server

[Jerry2]

Dear Netapp experts!

Could you please help us troubleshoot the following error?

Issue: Unexpected NDMP error communicating with tape server (it is Commvault Media Agent server]

Detailed description : Our NDMP backup runs very slowly (approximately 2MB/Sec) and eventually enters a pending state with the error above.

Has anyone experienced this issue or have any insights? How to troubleshoot failing and slow NDMP connection?

[Gmox · Accepted solution]

Hello,

You may check these KB:

https://kb.netapp.com/on-prem/ontap/DP/NDMP/NDMP-KBs/Slow_NDMP_backup%2C_restore%2C_or_ndmpcopy_performance_with_insufficient_TCP_packet_window_size_f...

https://kb.netapp.com/on-prem/ontap/Perf/Perf-KBs/Slow_NDMP_when_Media_Server_is_located_in_different_subnet_range#:~:text=Slow%20performance%20observ....

[Jerry2]

Hi all,

we have finally found the solution for the error in the NDMP communication. Firstly, there was a significant packet loss (approximately 20–30%) associated with a specific interface/port, which required remediation. Moreover, intercluster communication/ports on the NetApp had to be explicitly allowed in the corresponding Vserver.

Moderators, please feel free to mark this post as the accepted solution. While the contribution from @Gmox  was insightful and appreciated, it did not resolve the underlying issue.