Website Just Stopped Loading This Morning, Renaming VAR Folder Solved It

[mwoes]

Today, our website refused to load. The error_log file in the root reported a lot of "No such file or directory" errors.

Although the website is working correctly after renaming the VAR folder, I'd like to know why something like this might happen. I am going to guess that it was a cache issue, but what would cause it to become invalid?

Magento version is CE 1.9.2.4, by the way.

Thanks

[Sinisa]

It could be either wrong directory permissions or cache issue. In var folder there are:

 - cache data

 - log files

 - session data

 - backup data

All of those could be offloaded to the other places (for example if you're using Redis for sessions/cache, or ELK stack for log files). So, you could lose important data, but it's nothing that you cannot live without. I recommend you just to make full backup of your website, if you don't have it.

Session data was the only important thing there, it may happen that your Customers will have to add product to cart again, if they were in the middle of buying process.