Depending on what the OP is paying for their web hosting service, I might could understand a 1MB/s I/O limit.
But, in my experience – admittedly this was several years ago – we toyed with CloudLinux limits and had a lot of “cheap” accounts. So the idea was to intentionally have their limits like this set real low. The purpose being to encourage them to upgrade if they were really using a lot of resources. We used a 1MB/s limit as our entry point.
We found that setting the disk usage to 1MB/s on these accounts severely undermined server performance. Server loads went from averaging 3 to 4 to upwards of 40 to 60.
We then went to testing raising the disk I/O limit for the entry point. I don’t remember exactly what we settled on, 8MB/s seems vaguely familiar. But the point was, once we set it high enough to get server performance back to stable… there was no longer any incentive to encourage these “cheap” accounts to upgrade.
That’s what started my thinking of “what’s the point of limits if you have to set your entry points so high that there’s no incentive to ever upgrade?” line of thinking.
Entry point in this context means your lowest priced account, your minimum limits.
If your average account is using 1 CPU, 512MB Memory, 4MB/s I/O, 1024 IOPS, etc. And if you have to set your entry level limits to 2 CPU, 1GB, 8MB/s I/O, 4096 IOPS just to keep your server running optimally… then what’s the point of anyone ever choosing anything more than your entry level plan? Why offer any plans other than your entry level plan? What’s the purpose of having these limits if they’re not really used?
In regards to the OP’s issue – I’d say the 1MB/s I/O certainly isn’t helping. But the question would be, is the OP on the host’s entry level plan? And are the host’s servers performing optimally? Is a 1MB/s I/O limit on this server for many accounts, dragging down performance completely on the server?