My programmer just built an application with PHP using Doctrine ORM (will be a high traffic social networking website), and it's very heavy in PHP/Apache and CPU. The queries are wonderfully fast, and MySQL is barely using any CPU, it's just Apache.

I was curious to if an SSD would help speed up PHP/Apache, because I know the bottleneck is in PHP reading multiple files, class files, and loading up a bunch of data.

So common sense makes me think if PHP is reading multiple PHP files, an SSD would only help as far as read/write?

I was thinking of doing a high performance SSD for the PHP application, but for user image uploads, I would just continue using a 15k SAS. Is there any performance issues regarding using an SSD in this kind of situation? And would it prove to help speed up PHP/Apache, and help the CPU problem out?

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Switching to a long-lived application daemon would help more. – Ignacio Vazquez-Abrams Jul 17 '11 at 3:36
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Unless PHP is constantly pulling different data from the disk, it'll get cached quick and never hit the disk again. I'm with Ignacio on this one. Adding RAM might increase the cache hit ratio too. – Chris S Jul 17 '11 at 3:41
long-lived application daemon? – Andrew Fashion Jul 17 '11 at 3:45
Andrew fashion, you do use a php opcode cacher, right? – 3molo Jul 17 '11 at 5:09
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Then an opcode cacher is probably what you need. – 3molo Jul 17 '11 at 6:03
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The only time you'll get an increase in performance is if your system profiling shows that you're currently bottlenecked on disk I/O. Does your system profiling show this?

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I'd better profile your code to see where bottlenecks really are, as good SSDs are pretty costly and (at first glance) won't give you that much performance gain for that money.

What's load level you have now? Is it test system or production server with 1000's of users on it?

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Oh, I see number for the load up in the comments. But what hardware (CPU and RAM at least) you're put on it? – Alexander Apr 18 at 6:16
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