Very rare: I/O Usage limit reached when Caching turned ON

[spanishcivilwarstamps]

Hello,

 

I have a very curious case for which I cannot understand the origin:

 

I've noticed a very slow upload time for my website, and when this is happening, also the server reaches the I/O Usage limit (which is 2500 KB/s). This only happens when clicking on some categories, but never when clicking on homepage or products page. In some other categories apparently there is neither this problem.

 

If I disable Caching under Advanced Parameters - Performance the problem disappears. So what is intended to consume less resources if active, exhauts the I/O Usage limit if enabled and brings usage to normal if disabled.

 

24 hours before this was not happening and all was normal. Any idea of whan may have happened?

 

Thank-you

[Gabriel Perez]

Hi.

 

We had a similar problem, also reaching the limit on certaing categories, and only when caching enabled.

In our case, it happens that the theme we were using had a lot of nested foreach (im talking about 10-15) on the category.tpl

 

Hope that helps.

[spanishcivilwarstamps]

Here are the server's resource usage charts of the last 24 hours. I've searched for SQL injections and malware scripts with no results.

I/O and phisical memory usage still at maximum if filesystem cache is turned on. Any other idea?

[bellini13]

Of course disk I/O is going to increase (significantly) if you enable a feature that is constantly doing reads/writes to the file system.  Just because the feature is there, doesn't mean that it is effective.

[spanishcivilwarstamps]

I agree Bellini13. But just 36 hours ago this was not happening, with that feature enabled. Even after disablig that the issue has occurred one more time, but has not repeated anymore after that single time.