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 th...
Failed to boot after kernel upgrade
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 erro...
segfault and error 4 in libc-2.12.so
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 messag...
Multiple version issue of glibc-common package on RHEL systems
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...
How to display the obsoleted packages and versions of a RPM?
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 g...
Xntpd restarted due to no time server selected
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 s...
The difference between IP address and Hostname when creating SSH User Equivalency
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:
$ ssh -o FallBackToRsh=no -o PasswordAuthentica...
VirtualBox VM caused system hung after laptop upgrade
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...
ACFS-9459 & ACFS on Oracle 11.2.0.4 and RHEL7.4
Sometimes, when I installed the Oracle GI and run the asmca, I could create volume and acfs easily, while I never know the background of such things.This time, I need to create a shared cluster fi...
LinuxCould not boot after kernel upgrade
I got this issue last afternoon and fixed it this noon, so maybe it could help others.Some people prefer to install the RHEL on their servers while do not want to purchase the service, so to get u...