It is a really easy task while I cannot find a complete command list to finish it, so I list the commands here to help others having similar request. yum install -y yum-utils device-mapper-persistent-...

Several weeks ago, One of our guys pressed the 'Upgrade' button of Jenkins, and after that it could not work any more. Of course he should not do this as he totally did not know the result, while I al...

Today my friend upgraded some nodes and a small part of them failed to boot after the upgrade. He checked such systems and reinstall the new installed kernel, then reboot them and we could enter the s...

Last night we upgraded some servers and one of them could not be accessed using SSH. I checked it on the vCenter and found it entered emergency mode and showed some messages on the screen. The error m...

These days I helped to troubleshoot a RedHat Cluster issue. When we run command 'service cman start' we would get a 'FAILED' result and from the /var/log/messages I found below similar error message: ...

These days we are doing some maintenance tasks on hundreds of RHEL servers and we update them using a shell script. We failed to update part of them and after I fixed the failure I would like to share...

These days I patched some servers using a standard script and it run successfully on most nodes until last night. It failed on two nodes and the primary issue was about the python34 package. I got bel...

Handled a ntp issue these days and I want to share my learning here as I could not find the right and detail explanation until now. The error message was like the title and when I checked the ntp serv...

I provided a 12c RAC step-by-step installation guide to client and he got issue during the deployment. Be specific, he failed the SSH User Equivalency: [grid@rac122-1 ~]$ ssh -o FallBackToRsh=no -o Pa...

In last week I upgraded my laptop from T420s to E485 to get maximum 32G memory also because the T420s was so old and the cooling system worked inefficiently, so during the summer it would become slowe...