I/O usage limit

Is your I/O usage limit reached on your server? Here’s the reason for high I/O usage and how you can fix it.

The limit is often implemented in a shared hosting environment. CloudLinux LVE technology allows the hosting providers to set limits to maintain the proper security and integrity of the server.

If you have more WordPress plugins, your I/O usage might constantly go in red. It’s because each plugin sends multiple read/write requests which might exhaust the limit.

But what plugin causes the issues? And, what if you are not using WordPress?

Let’s find out everything you need to know about the I/O limit and how to fix the usage limit of IO.

What is the I/O usage limit in web hosting?

In web hosting, it is the throughput of data transfer between RAM and hard disk. To understand in simple words, the speed of the data transfer between RAM and SSD (Or HDD i.e. Storage) is the input/output limit.

If your website reads a lot of data from the web server, you might exhaust the limit. If your I/O (input/output) usage limit exceeds, your website will hang for a while. It will be back to normal once the transfer is completed.

You might wonder how much time it will take to get back to normal, right? Let’s understand the concept in a little more depth.

The IO limit is set to restrict the data written on the storage disk. The limit that you see in your hosting account is the limit per second.

If you are running a resource-intensive app, the limit will be exhausted soon. Some of the examples of resource-intensive apps include a streaming website, online gaming, etc.

The limit will also be reached if you are taking a backup or restoring it.

Once your limit is reached, the speed goes to a bare minimum or zero, so your website becomes extremely slow (almost non-usable) once you reach the IO usage limit.

Once the process is completed, the I/O usage decreases and your website goes back to normal.

Why is my I/O usage so high?

Usually, I/O usage is high when your website has too many read/write requests. For instance, a streaming service will have a constant exchange of data.

If multiple users are streaming in Full High Definition quality (FHD), the I/O usage goes high.

So, there are multiple reasons for input/output usage going high. Plugins using read/write features such as backup, streaming service apps, etc. are some of the places where you should have a look.

Let’s see how you can identify the cause of high input-output usage in WordPress or cPanel.

Identify the cause

WordPress

To identify the cause, you can install a plugin such as Query Monitor. It will help you identify the plugins using most resources and I/O.

It basically monitors how much resources are being utilized by the queries of the database.

cPanel

cPanel has a metrics section where you can see the resource usage. It will also include CPU usage and I/O usage.

Further, to take it a step further, you can also have a look at the error logs.

How to reduce I/O usage in cPanel?

Once you identify the issue, it’s time to reduce I/O usage in cPanel. The steps also work if you have a different panel.

Install Caching plugin

Any caching plugin will do the work. However, for the best output, we recommended going with the paid plugin. WP-Rocket does an excellent job in caching your website and reducing resource usage.

Use CDN

CDN helps you distribute the load of your traffic. It serves the website from the nearest location to the user. Most hosting providers allow easy integration with Cloudflare.

Even if your hosting provider doesn’t, you can easily do the process manually.

Use Trusted WordPress Plugins and WordPress Themes

Avoid using cracked or nulled versions of any plugins or themes. These nulled plugins are infected with malware or spyware.

The malware may use an enormous amount of resources leading you towards the I/O usage limit being exhausted.

Backup plugins

Like we are constantly mentioning the backup plugins, this is one of the biggest reasons why your I/O limit gets drained and is shown in red.

If your website is huge, the backup plugin has to send more read and write requests. You might think, the backup is running in the background. However, this might use a huge amount of resources.

So, what’s the solution? It’s best to take the backup during non-peak hours. People often schedule their backups when there is the least amount of traffic (usually at midnight).

UpdraftPlus (free) allows you to do that.

Optimize Database queries

This applies if you have custom code on your website. You can optimize the queries.

For instance, instead of using “select * from table_name….”, you can use “Select name from table_name….”.  Because the use of * asks the database to return all the columns from the database table instead of the only needed column(s).

This utilizes more resources.

This small change can help you decrease the I/O usage as well as increase the speed.

If your PHP scripts have multiple queries, make sure they are properly optimized.

Delete unnecessary plugins

Let’s be honest here, we all have a habit of installing a lot of plugins, and our laziness to remove those is increasing the resources.

So, it’s time to deactivate the plugins and delete them if you are not planning to use them in the future.

Should I increase my I/O limit?

The I/O limit is different from other resource limits. Even if the I/O usage goes in red, it doesn’t generate errors. It simply slows down your website.

The server then waits for the data transfer between RAM and hard disk.

Once the transfer is completed, the I/O usage goes back to green and your website works as usual.

It’s worth noting that if you are experiencing the I/O limit only for a few seconds, optimizing the website will help you. In this case, you don’t need to increase your I/O limit.

Also, increasing the I/O limit will not fix every issue you have that causes your website to hang. The I/O enhancements are only useful if you have a resource-intensive website such as a tool or streaming site.

So, you should keep an eye on when the I/O limit is reached and for how many seconds/minutes the I/O limit stays in red.

Please note that in most shared hosting services, it might take a few more seconds to update the resource count. So, it’s recommended to check the resource chart.

What is the difference between I/O and IOPs limits?

People often confuse I/O and IOPs limits. Here’s the main difference between these two in layman’s terms.

• IO Limit: IO limit is how fast a group of people can enter a hall from a small door.
• IOPS limit: IOPS is about how many people can enter the hall from a small door at the same time.

Let’s see what it means in technical terms.

• IO limit: Maximum speed limit of data transfer (read/write) between the server’s hard disk and RAM.
• IOPS limit: The number of times you can read/write on the disk per second. The size of the operations may vary. It can be 4k read/writes per second or it can even be 64k read/writes.

The base formula to get IOPS is  {(Throughput in MB/s) / (KB per IO)} * 1024. If the throughput is 2 MB and the size of each operation is 2 KB. The IOPS is (2/2 = 1 * 1024) 1024 IOPS.

Conclusion

The I/O (input/output) usage limit is necessary to prevent users from abusing the resources and to keep the server secure. A high I/O usage in one account can lead the entire server to slow down.

To avoid this, there are I/O limits implemented by the hosting provider.

If you keep reaching the limits, you can surely opt for a VPS or dedicated servers. Please note that a VPS will still share I/O with other users.

However, with VPS, you will get higher limits as compared to shared hosting.

I/O is a small factor that decides the speed. Your other resource usage as well as your website’s optimization plays a very important role here.

If you are running tight on budget, you can opt for a shared hosting that has at least a 4 MB I/O limit. A cheap VPS server is a good alternative to it.

FAQ (Frequently Asked Questions)

What is the IO limit in hosting?

The IO limit is the hosting provider limit on the maximum speed of read/write transfer between hard disk and RAM.

What is high disk IO usage?

High disk IO usage is seen when there are multiple read/write operations. It gives insight that maximum speed is utilized. The IO usage goes back to normal once the transfer is completed.