What To Do When Hitting Your IO Limit

When your service is hitting its I/O limit, this can cause slow loading on your website. This article will go through troubleshooting those issues!

What is I/O Usage?

I/O Usage is essentially how much disk activity is being used at a given time, this can be due to:

• Database queries
• File uploads and downloads from your website
• Log writing
• Cache generation

If your I/O limit is being reached, our servers put new processes to sleep until resources are available.

How to check your I/O usage

1. Login to cPanel.
2. Scroll down to the ‘Metrics section’ → ‘Resource Usage’ and click on ‘Current usage’ tab.
3. Scroll down till you see “Input/Output Usage”
4. If the graph is flatlining at the top, the site is maxing out its allocated disk speed, causing the site to load slowly.

Troubleshooting

Backup plugins, Cron jobs and scheduled tasks

High I/O usage is usually caused by plugins, cron jobs or scheduled tasks on your website, this can include:

• Backup plugins which are performing a backup or restore
• Image processing plugins
• Unoptimised caching plugins writing cache files
• Cron jobs or scheduled tasks which perform any read or write tasks

A few things to look into could be:

• Take a look at the spikes in I/O usage, do they correlate to a scheduled task, or a backup plugin?
• Try installing a query monitor plugin to see more verbose information about the requests on your website and what is consuming the resources.
• Optimise any media on your website (e.g. Images or videos) to compatible formats so they are able to load quickly, pair this with a caching plugin like LiteSpeed Cache.
• Ask your developer to review the site code and/or disable any unused plugins.

Visitors

• If it’s genuine traffic: We recommend to install a caching plugin, this will allow your site to handle more visitors and serve the content quicker. If you’re reaching your resource limit, you may need to upgrade.
• If it’s malicious traffic: (e.g. lots from foreign regions), block IPs following this guide.

Database queries/log writes

High I/O usage can be caused by long running or poorly optimised database queries, or errors on your website that are writing to the database or a local log file like error_log or debug_log. You can try:

1. Optimising your database using PHPmyAdmin.
2. Checking any long running queries using PHPmyAdmin.
3. Check your error logs, if the errors are recent and the file size is large, this can be causing your I/O usage. Look to resolve the error.
4. Check to see if you have debug mode enabled on your website, if so, look to disable this if it’s not needed.
5. Consult with your developer to look into and optimise your database queries.

Need a pointer?

If you’re not sure where the issue could be, feel free to submit an eTicket to our technical support team with your issue, and as much information as you can provide (e.g, What date, time, how often its happening and what website) and our team can take a look for you.

Note: We can only look, resolve and rule out issues at a server level. If its due to your website, we recommend to reach out to your developer for assistance.