How do I know if a Dedicated CPU plan will help?
I'm trying to determine whether it will be beneficial for me to migrate to a Dedicated CPU linode?
The CPU usage graph tells me that my Linode's average CPU usage is 135%? How can it be higher than 100%? Is it because I'm using a plan with 4 cores?
The primary benefit of a Dedicated CPU plan is that you would never have to worry about other users on your Linode's host tapping into your CPU resources, nor would you have to worry about tapping into theirs, and you can expect that the CPU's performance will be more consistent. Whether or not it will ultimately perform faster than a shared plan depends on a variety of factors, and in some cases you may find that a shared CPU still performs better in it's day to day use.
You are correct that the reason you are seeing more than 100% usage on your Linode is that you have a 4-core plan. In this case, full usage of all 4 cores would be represented as 400% (100% per core).
The best way to tell if a dedicated CPU plan is appropriate for your use case is to monitor your Linode's CPU steal value, particularly at times when it is performing slowly. You can view this value by running the following command on your Linode (via SSH or LISH):
iostat 1 10
This will take a few minutes to run, as it will repeat the command 10 times. If the steal value is under 10%, then this is considered normal, but anything higher and it may be necessary to take action. It is not always necessary to go straight to a Dedicated CPU plan, as we may be able to simply migrate your Linode to a quieter host. The migration can typically be performed with no downtime and is always at no additional cost.