Overview

This topic describes some typical PTT issues that occur during operation and how to troubleshoot the issues:

• Direct Copy Issues
• NBU Drive Stability Issues
• Slow Performance on NDMP PTT from DXi to Scalar i500 Drives
• Error occurs indicating that DXi is not an NDMP host

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Most Common Issue: Direct Copy

The most common PTT issue that we see in Supoport is Direct Copy not working properly. When a NBU duplication job (write from virtual media to physical media) is started, NBU will automatically attempt to use Direct Copy. When Direct Copy is not working, NetBackup uses available data paths to get the desired data to tape. PTT is still working; the data just takes a different path than expected.

 

How to Identify this Issue: You can identify this scenario in DART. You will see FC OUT mirrored by Ethernet IN. It is possible that we have some customers using PTT where Direct Copy is not working properly, but we are not aware of this, because we have not looked at DART.

 

In 1.4.x, if Direct Copy is working properly, the FC and Ethernet graphs in DART will show no activity. An example of what DART looks like when Direct Copy is not working is shown below:

  

 

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NBU Drive Stability Issues and One Potential Cause

When Direct Copy isn't working and large amounts of unexpected data hit the media server, the NDMP paths for the VTL drives and the NDMP physical drives will often be put into a down state in the backup application. This can also be caused by a poor SAN configuration.

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Slow Performance on NDMP PTT from the DXi to Scalar i500 Drives and How to Resolve

If you notice slow performance on PTT from the DXi to the Scalar i500 drives, validate that the DXi is sending/receiving data. If it is, make sure that within NBU the DXi is set up as the NDMP-Host, not using the IP address of the DXi because the DXi writes data to tape using NDMP.  Refer to the Symantec NetBackup Application Specific Configuration Guide for configuration details.

 

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Error occurs indicating that DXi is not an NDMP host

 

 If NBU is configured to use the IP address of the DXi, NBU will send a command to the DXi for direct copy to tape The DXi will respond with an error indicating the DXi is not an NDMP host because it knew itself as the hostname and NBU's request was for an IP address.  NBU will then issue the command to duplicate the data using standard “bpduplicate”, the data will then move from the DXi to the media server, via the network, and then back to the DXi via network to the tape drive. This "bpduplicate" activity will be limited to the speed of the Network.

 

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What's Next?