I have been dealing with this weird issue for the past days:
All of a sudden our page load time jumped to over a minute and the site kept crashing. The server load was higher than usual but not alarming. Just the response time was off the chart.
Our server provider told us that this was due to some sort of script in our cs cart dir and they would also swap a drive which showed bad performance.
After a lot of back and forth I isolated the problem to the images in a handful of recently added products. The problem was that somehow the images uploaded there managed to bypass our image file size limiter. With each image about 15mb in size it was no wonder things weren't working.
So deactivated the products, rescaled the images and replaced them directly on the server, cc'd and ct'd and activated the products again but things did not really change.
I already reached out to cs cart support about this but since the reaction was pretty slow I kept on digging and found out that the source images had some weird color profile attached to a cmyk color space and this was causing a lot of problems with the frontend display and imagick.
I corrected the images and manually uploaded them to two of the problem-products - Eureka! It worked!
So I explained my colleague how to process the images and then re-upload them to the products.
This is where things went sour.
Server system load spiked to 90% and the site immediately shut off.
Once the server settled down I deactivated the problem-products again and everything worked fine again.
I am still waiting on cs cart support for an update but since they did not find anything particularly wrong before I am afraid they will not find anything now - plus the response rate is pretty slow.
I cross-checked the cs cart logs with the server system load graph, and they perfectly align.
What can I do to further analyse this? has anybody experienced something similar?