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POApache KeepAlive on API Server
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copied!<p>I have a LAMP server (Quad Core Debian with 4GB RAM, Apache 2.2 and PHP 5.3) with Rackspace which is used as an API Server. I would like to know what is the best KeepAlive option for Apache given our setup.</p> <ul> <li>The API server hosts a single PHP file which responds with plain JSON. This is a fairly hefty file which performs some MySql reads/writes and quite a few Memcache lookups. </li> <li>We have about 90 clients that are logged into the system at any one time. </li> <li>Roughly 1/3rd of clients would be idle.</li> <li>Of the active clients (roughly 60) they send a request to the API every 3 seconds. </li> <li>Clients switch from active to idle and vice versa every 15 or 20 minutes or so.</li> </ul> <p>With KeepAlive On, the server goes nuts and memory peaks at close to 4GB (swap is engaged etc). With KeepAlive Off, the memory sits at 3GB however I notice that Apache is constantly killing and creating new processes to handle each connection. </p> <p>So, my three options are:</p> <ol> <li><strong>KeepAlive On and KeepAliveTimeout Default</strong> - In this case I guess I will just need to get more RAM.</li> <li><p><strong>KeepAlive On and KeepAliveTimeout Low (perhaps 10 seconds?)</strong> If KeepAliveTimeout is set at 10 seconds, will a client maintain a constant connection to that one process by accessing the resource at regular 3 second intervals? When that client becomes idle for longer than 10 seconds will the process then be killed? If so I guess option 2 looks like the best one to go for?</p></li> <li><p><strong>KeepAlive Off</strong> This is clearly best for RAM, but will it have an impact on the response times due to the work involved in setting up a new process for each request?</p></li> </ol> <p>Which option is best?</p>

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