Check the cause of slow loading time among different server

A e-shop has developed using perstashop and put to the three server:

the first 2 is amazon, should be same setting

Server 1:

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Server 2:

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the last one is just local hosting

Server 3:

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The problem is server 1 loading very slow compare to the other two server, but the performance should be the best among 3.

It looks as if server 1 hasn't cache the files

but in fact, all of them has

turn on smarty cache, using file system , with recomplie when modify
and
turn on the file system cache

Given that the code and server setting are the same, both 2 amazon server is same setting, and localhost one is other server, however it should be slower than server 1

1) How to debug/ check whether the file is using cache already?

(the cache file locate in cache/smarty and cache/cachefs in server)

2) And what takes the long load time for server 1? Just consider it as an PHP site, any ways to check why it is slow?

Thanks a lot for helping

I am giving answer of your 2nd question.

I dont't know the exact problem of slow loading. but We had faced same issue in one of our projects in last month. Server was amazon.

One of our Instance was very slow. We had tried many solutions but none of them were working. Then We have found a solution which looks very unfair but it Worked for us.

We had Just restarted the slow Instance and We got success.

I hope this solution will work for u also.

All the Best :)

Refer to the comments - I misinterpreted the data I was looking at earlier. It appears the server can only handle maybe 5-10 requests at a time so things get blocked until the other things are done loading. You likely just need to update your web server's configuration to handle more requests.

There is also a lot of JS data in the file. It is 318KB just to load the page and it has to do many requests to get JS/CSS files before it even gets to any of the HTML. So it is 318KB + all the external JS/CSS it needs to fetch (wow!). That's like 4MB of stuff just to load a page.

Check the modify timestamp on the files generated by your caching system to verify that caching is working.

Edit:

Since there is now a bounty out - please review the comment discussion we had. There is an issue where a traceroute doesn't make it to the server destination and I suspect that is related to the slowness but that type of network issue is over my head.

Answer to question **1**:
You can use *chromes developer* tool, F12, and then network tab. It will show you all the files being downloaded, in the size column you can find if it's being loaded from cache or not.<br/>
Answer to question **2**:
You can use *chrome's YSlow plugin*. it will help you a lot, but is obvious about your site you have too many files; css, js and lots of images; try to merge your css and js files and use image map for your images.
Hope you can solve your problem

No body can clear answer what is problem with servers. But you can find it with profiling. If you have budget i highly recommend to you buy a profiling tool "Tideways.io", "Blackfire" or "New Relic". I used New Relic, and it really help full to find bottlenecks. If you don't have budget to get a profiling tool you can use php profiling extension Xdebug. It is help full too, but reading profiling output of xdebug can be a bit difficult. But it's setup is really easy, and you can do partial profiling ( you can profile url which you want) with "xdebug profile trigger" instead profiling all requests.

Use this google solid tool to get insight about your page performance.

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.

Also check if server1 is matching server2 configuration.

This tools shows me lots of suggestions for improvements for your website.