Sharing my experience DSMC command failed in TSM

 

 

Hello friends,
In this blog, I want to share my personal experience about troubleshooting the DSMC command failed issue in IBM Spectrum Protect (TSM). This post is written in my own words, so please ignore any spelling mistakes or grammar errors. My only goal is to help other beginner TSM administrators like me who might face the same problem.

A few days ago, I faced a DSMC command failed error while connecting a client system to the IBM Spectrum Protect (TSM) server. We tried multiple solutions, checking configuration parameters, reviewing settings both on the client and backup server side, and searching online for solutions. We even checked IBM documentation and community pages, but nothing seemed to work at first.

It was a bit frustrating, but the experience helped me learn more about TSM connectivity, configuration validation, and troubleshooting steps.

Sharing my experience DSMC command failed in TSM

I’m sharing a little bit of the knowledge I have about TSM from my own experience. Currently, I’m working on IBM Spectrum Protect Fix Pack v8.1.13.100, and in our environment, we have installed the TSM client 8.1.11.0 on an AIX server. In this blog, I’m going to talk about some of the issues and small errors I faced especially the DSMC command hang issue and how we tried to troubleshoot it step by step.

My purpose is to share this information with others who might be facing the same problem, so it can be helpful for them. We searched through many articles, forums, and even the official TSM/IBM sites, but we didn’t get a satisfactory solution in the beginning. That’s why I decided to write this blog, so beginners like me can benefit from what I learned.

That’s why I am sharing this DSMC command failed issue and the correct solution here, so it can help others who face the same problem. Hopefully, this will make troubleshooting easier and allow them to fix the DSMC failed/hang issue faster. Earlier, I had posted a blog about how we migrated and updated our IBM Spectrum Protect Server from v8.1.13 to v8.1.13.100, but at that time I did not mention an important point.

During that update, we had to copy the client files to the AIX machine, but some AIX client servers did not have enough space in the /tmp directory for the updated STA Agent/Client installation. Because of this lack of space, certain components wouldn’t install properly, which later contributed to the DSMC command issue we were facing.

When the DSMC command fails to connect to the backup server, there are many common reasons behind it. Most of us already know the usual points we find on the internet or deal with in our daily backup administration tasks. But in our case, this issue was completely new and unexpected. Honestly, every TSM issue doesn’t always mean data loss, corruption, or a major crash sometimes it’s a small configuration or environment-related problem that creates big headaches.

For DSMC connection failures, the common checks include:

• Pinging the client server (network connectivity)

• Backup/TSM communication port not opening

• Permission issues with dsm.sys or dsm.opt files

• Certificate / SSL or session security mismatches

• Configuration or path issues on the client side

We verified almost every parameter on the AIX client server. Interestingly, other AIX clients in the same environment were able to connect successfully to the IBM Spectrum Protect server using the dsmc command. Only a few specific servers were failing and showing the error:

IBM Spectrum Protect session could not be reestablished

This made the issue more confusing because the environment was the same, but the results were different.

We spent almost 9 to 10 hours troubleshooting this issue. The same connection failure kept appearing in the dsmerror.log, no matter what we tried. Finally, we decided to remove the AIX client and perform a fresh installation. After reinstalling the client, we gave the required permissions to the necessary files, took a backup of the certificate files, and copied the new cert and configuration files from the TSM server.

After that, we started the dsmcad service, and it worked. Even the dsmadmc command started connecting properly. However, the dsmc command was still hanging, which meant the main problem was not fully solved yet.

At this point, we raised a Severity 1 ticket with IBM Support. IBM responded quickly and cooperated well during the troubleshooting. They asked for logs first which is standard for faster diagnosis and we shared all the required log files with them. After reviewing the logs, their initial feedback pointed towards a communication issue, and they advised us to check with the network team as the next step.

We also contacted the network team to check if there were any connectivity issues, packet drops, or network fluctuations between the client server and the backup server. But even after verifying everything from the network side, the problem was still not resolved. At this point, we were running out of options. IBM Support was helping in parallel, but since the affected server was part of our production environment, we needed a solution urgently. Around 4–5 servers were affected, while other servers were working fine, which made the issue even more confusing.

We were stuck for a long time, and honestly, our minds were blocked from trying so many possibilities. We reached out to multiple people who work on IBM Spectrum Protect/TSM and took guidance from wherever possible. Because as every backup administrator knows, jab tak issue resolve nahi hota, tab tak ghar nahi janeka, troubleshoot karte rehneka,  we don’t stop until the issue is fixed.

Root Cause Story: Why the DSMC Command Was Failing

While troubleshooting the DSMC command failed/hang issue, we kept asking ourselves the same question: Why is this happening? We even checked with the AIX team to see if there was any hardware problem or disk issue from their side. They verified the system using the errpt command, but nothing unusual or related to the failure appeared in the logs.

Finally, one of our AIX administrators remembered something important:
During the upgrade activity, we did not have enough space in the /tmp directory, so we temporarily mounted an NFS mount point as a workaround on the affected AIX client servers.

We knew about this earlier, but it didn’t “click” in our mind that this could cause the DSMC command to hang. Since dsmadmc was able to connect and work properly, we kept assuming the problem was elsewhere. This made the issue more confusing because dsmadmc was running fine, but dsmc was failing, which pointed to a more complicated scenario.

In reality, the lack of local /tmp space and dependency on NFS during the client upgrade was the key reason behind the DSMC hang issue.

Final Discovery & Fix

When we checked the filesystem space on the affected server using the df command, the system went into a hang state and didn’t return to the prompt. Normally, after running df, it should display all mounted filesystems and return back to the # (hash) prompt, but on this server it never came back, we had to interrupt it manually with Ctrl + C. This behavior confirmed that something was wrong at the filesystem or mount level.

The DSMC command failed issue turned out to be related to the NFS mount point we had added earlier due to low space in the /tmp directory. Because the NFS share was mounted and not responding properly, both the df command and the dsmc command were getting stuck. This is the reason DSMC was hanging and not connecting to the IBM Spectrum Protect server.

Finally, after we used the command below to force unmount the NFS mount point:

umount -f <mount_point>

…everything started working again.

The dsmc command executed successfully, and the client server connected with the backup server without any issues.

This confirmed that the NFS mount issue + lack of local /tmp space was the root cause behind the DSMC hang problem.

Conclusion: Final Understanding & Learning

It now makes sense that the dsmc command checks AIX filesystem parameters before it fully executes. Since the binary is located in the default path:

/usr/tivoli/tsm/client/ba/bin

…it expects the system to respond normally. But because the df command was hanging due to the problematic NFS mount, dsmc also got stuck while trying to connect to the backup server. When the filesystem check fails or hangs, the DSMC process cannot continue, and it eventually shows errors like “session could not be reestablished” or connection failure.

After we force unmounted the NFS mount point, the problem was solved and:

• df command started working normally

• dsmc command ran successfully

• All agents connected to the IBM Spectrum Protect server without issues

Now everything is working fine.

Final Message

So friends, if you ever face a similar issue, try to think about why it is happening instead of assuming it’s a major crash or data loss situation. As I always say, every TSM issue is not a disaster, sometimes a small configuration or filesystem problem can block everything. 🙂

I’ve solved many TSM issues before, but this one was something new and took our troubleshooting to the next level. We kept trying until it got fixed, and that’s what makes every backup administrator stronger. 💪

IBM products are truly reliable, and every issue we face teaches us something new. We learn, troubleshoot, and grow with experience. Thank you, IBM, for the product and the support.

So guys, that’s it for this blog! I hope you got a clear idea of how we resolved the DSMC command failed problem in IBM Spectrum Protect. If this information helped you even a little, please share it with others who might be facing the same issue. It may save their time and effort.

Please ignore any English or spelling mistakes, I’m still learning, and I’m just sharing my experience so it can help beginners in the IT sector, especially those working on IBM Spectrum Protect/TSM.

Thank you for reading till the end.
Best of Luck, and Happy Troubleshooting! 🙏