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...
Archivelog backups were not removed per backup policy
Suddenly our support guys found some archivelog backups were not deleted even they were not needed by the backup policy ( recover window of 7 days). At the beginning I thought maybe it was a similar i...
Moved site to Aliyun International
HostKVM is a great VPS provider and I got almost perfect service from it! Every time I got any issue, I would ask help from them and got resolved really soon. And for this reason I did not move out fo...
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 message: ...
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 got bel...
Talking about ‘recovery window of 7 days’
Sometimes we will keep the database backup for one week and set the retention policy to 'recovery window of 7 days'. So we will only keep the database backup for 7 days, right? In fact, it depends. If...
ThinkPad E485 memory compatibility issue
For a long time I used my old T420s laptop as primary device while it could only support 16G memory. So at the beginning of June, I bought a new laptop ThinkPad E485 which had 8 CPU cores and could su...
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 serv...
PVG concept in AIX LVM
Long time ago, when I studied the Veritas LVM, I knew the PVG term which meant physical volume group and the physical volumes in the same PVG were from the same SAN or same disk. Usually there is a si...
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