WordPress Admin from the 3rd day of using got very slow, worked first 2 days perfectly, what could be the issue?

t2 type is burstable one

Burstable performance instances provide a baseline level of CPU utilization with the ability to burst CPU utilization above the baseline level. The baseline utilization and ability to burst are governed by CPU credits. Burstable performance instances are the only instance types that use credits for CPU usage.

Each burstable performance instance continuously earns credits when it stays below the CPU baseline, and continuously spends credits when it bursts above the baseline. The amount of credits earned or spent depends on the CPU utilization of the instance:

• If the CPU utilization is below baseline, then credits earned are greater than credits spent.
• If the CPU utilization is equal to baseline, then credits earned are equal to credits spent.
• If the CPU utilization is higher than baseline, then credits spent are higher than credits earned.

For the t2.medium CPU credits earned per hour: 24 Maximum earned credits that can be accrued*: 576 vCPUs***: 2 Baseline utilization per vCPU: 20%**

• The number of credits that can be accrued is equivalent to the number of credits that can be earned in a 24-hour period. ** The percentage baseline utilization in the table is per vCPU. In CloudWatch, CPU utilization is shown per vCPU. For example, the CPU utilization for a t3.large instance operating at the baseline level is shown as 30% in CloudWatch CPU metrics. For information about how to calculate the baseline utilization, see Baseline utilization.

You can use CloudWatch to monitor your Credits

• CPUCreditUsage – The number of CPU credits spent during the measurement period.
• CPUCreditBalance – The number of CPU credits that an instance has accrued. This balance is depleted when the -CPU bursts and CPU credits are spent more quickly than they are earned.

If the instance is running low on accrued credits, CPU utilization is gradually lowered to the baseline level, maybe this is a reason of your app slowness.

Hi @Oleksi, thank you very much for your support. I checked the CPUCredit Infos that you have suggested. On the first view I can´t see an issue there, but will check and observ the development of the Numbers there.

The WordPress Admin is running today again normal and fast, maybe it was an temporary issue. I will check some tutorials for AWS where they explain everything from scratch and check where I can optimize the whole structure.

Will keep the Topic up to date when the issue pops up again or I find some optimization info that can be useful for others.

Have a good week.

Cheers Saisonplaner