One of the cool things that Oracle Linux support gets you, is access to Oracle Enterprise Manager 13 to manage your Linux systems. You can use EM for lots of things, like patching systems, monitoring systems, provisioning systems and more.
EM can do a ton of things for Linux servers, and while talking with a client, I pointed out that EM can do one of the tasks that was needed to try to resolve a performance problem. That task was to compare multiple Linux systems to see what is different between them. Doing this in EM is really easy and fast to do, regardless of the location of the OS. You can also use EM to manage systems both on-premises and in the cloud. The location is not important!
The first thing to check is to make sure that the systems are target in EM. In this demo I will show how this can be done, using two systems. One system, db12c is running in the Oracle Cloud, the other system em13c is running in my lab.
First, I navigate to the list of all host targets, to verify that I can see the hosts. Now, you just have to have the host targets in the system, they do NOT need to be online to compare.
Next, navigate to the host, by clicking on the name. In the example I will use em13c.bubba.local.
From there head to Host->Configuration->Compare
From here we will select the host that we want to compare this system to.
To do that select Add from the menu, then select the host ( db12c) and finally the Select button
You should see the host you want to compare against in the target list now. If you want to compare multiple hosts, you can select more than one when selecting the hosts after clicking on “add”
Next submit the job using the submit button. Optionally you can select a Comparison template. This is useful when comparing large numbers of targets and your only interest is in a subset of the data, like Host data.
The comparison job will take a few seconds or more to run.
Initially a ton of differences will be displayed. The system will even compare details like CPU speed, MAC address and more as seen in the following screen shot.
More often that not, the interest is more about the software version, or kernel setting,. The compared data can be narrowed down be selecting the areas in the “Configuration items (Differences) column on the left. In the next screen shot, the data was limited to the OS Properties and ulimits.
From here it can easily been seen that there are significant differences in tunable settings, like the fs.mount-max and other settings.
Feel free to explore the other comparison options, you will find this a VERY useful advantage when running down performance differences between servers.
If you have any questions about EM13, please drop me a note in the “Contact Me/Ask a Question” page on the BLOG.