Hello, I found some information for you that should be able to help you out.
OxyDac:
Hi and welcome to the forum
The IO limit is based on how much storage bandwidth your account uses. If you read and write many (large) files from your account, this generates high IO usage. Normally, IO usage is throttled to prevent a few big accounts from hogging all the storage read/write capacity, but accounts that consistently overuse the storage are suspended for 24 hours.
Amount of MB per second the scripts of your account are reading and writing from the underlying storage. If you have scripts that continuously read or write many files, or big files, on your account, that would lead to high IO usage
It could be Malware, all the way to some plugin, cron, etc.
Unfortunately, we cannot give you the exact cause
Admin:
The IO limit is a quite hard to understand how it works and it’s correlated with website usage. But looking at the website, I would guess that the multiple backup and migration plugins installed are what’s causing the high IO usage. Packing up and restoring a full site, especially from PHP code, is quite stressful to the server, so being limited like that is expected.
That’s just one more reason why we always recommend against using backup plugins: they stress the servers and blow through your resource limits.
I hope this can help you out!