We need an IIS expert who can optimize our web server for high-load scenarios.
Currently, we are using IIS 10 on Windows Server 2022 in conjunction with PHP 8.4 via FastCGI and MySQL 9.3.
When the server is under heavy load, we occasionally see HTTP errors with the code 500 in our IIS logs.
We can rule out that our PHP code is causing the errors; the PHP error log is completely clean. Furthermore, MySQL remains perfectly accessible during periods when the errors occur. Apparently, there are settings within IIS that cause IIS to respond with the code 500 once a certain number of parallel requests are received.
Our server hardware is very powerful and is only utilized to a limited extent by IIS; the total CPU load on the server is only around 10%, even during peak times.
In IIS, the Max Instances value under the FastCGI settings is set to 0, allowing IIS to dynamically size the php‑cgi process pool.
The Instance MaxRequests parameter and the PHP_FCGI_MAX_REQUESTS environment variable are currently set to 1,000. In our research for tips on optimizing IIS for high load, we often see recommendations to increase these two values. We're happy to do that, but according to the Microsoft documentation, this only affects the "maximum number of requests that a FastCGI application is allowed to handle before the process is recycled." Therefore, we wonder if increasing this value could actually prevent the 500 errors.
The Queue Length parameter is set to 1,000 in both the FastCGI settings and the Application Pool. We've read several recommendations to increase this value. However, to our understanding, triggering this threshold results in 503 errors that we don't see. Therefore, we're wondering if increasing this value would have an effect in our case.
The limits for Activity Timeout and Idle Timeout are set high enough so that they don't cause any problems.
Dynamic and static compression are both enabled in IIS.
Our next step would be to enable FREB for 500 errors to potentially gain further insight into what causes the errors.
Of course, we can provide you with all the information you need for analysis. Please note that we cannot grant you access to our server.
Attached you will find our my.ini and php.ini.
We would be very grateful if you could help us optimize IIS to ensure optimal hardware utilization and eliminate 500 errors under high load conditions when a large number of parallel PHP requests must be processed via FastCGI.
Documentary Video Editing Category: Adobe Premiere Pro, Audio Services, Final Cut Pro, Video Editing, Video Post Editing, Video Production, Video Services Budget: ₹1500 - ₹12500 INR
22-May-2026 04:02 GMT
Darth Vader Shoulder Armor Project Category: 3D Animation, 3D Design, 3D Modelling, 3D Printing, 3D Rendering, Cosplay, Costume Design, Illustration Budget: $30 - $250 USD
22-May-2026 04:01 GMT
CRM & Workflow Web Development Category: CRM, Database Design, HTML, Laravel, MySQL, PHP, RESTful API, Web Development, Web Design Budget: $30 - $250 USD
22-May-2026 04:00 GMT
End-of-Year Sale Email Campaign Category: Content Marketing, Copywriting, Digital Marketing, Email Campaign, Email Marketing, Graphic Design, Internet Marketing, Mailchimp, Marketing Strategy, Product Marketing Budget: $8 - $15 AUD
Camtasia-Expert Video Editor Category: Camtasia, Content Creation, Editing, Video Editing, Video Post Editing, Video Processing, Video Production, Video Services, Visual Effects Budget: ₹250000 - ₹500000 INR
22-May-2026 03:52 GMT
High-Engagement Gaming Twitter Replies Category: Article Writing, Content Creation, Digital Marketing, Facebook Marketing, Social Media Management, Social Media Marketing, Social Networking, Twitter Marketing Budget: $2 - $8 USD
22-May-2026 03:51 GMT
Migration & Education VA, Chinese/English Bilingual Category: Admin Support, Customer Service, Data Entry, Email Handling, English (US) Translator, Time Management, Training, Virtual Assistant, Web Search Budget: $8 - $15 AUD
22-May-2026 03:50 GMT
Azure Copilot Multi-Agent Setup Category: AI Development, Amazon Web Services, API Integration, Azure, Cloud Computing, Dynatrace, GitHub, Software Architecture Budget: $10 - $30 CAD
22-May-2026 03:49 GMT
Buscamos comercial freelance Category: Account Management, B2B Marketing, Business Consulting, Business Development, Customer Service, Lead Generation, Market Research, Sales, Sales Management, Sales Promotion Budget: $30 - $250 USD
22-May-2026 03:48 GMT
Catamaran Resistance and Propulsion Calculations Category: Engineering, Excel, Finite Element Analysis, MATLAB, Matlab And Mathematica, Mechanical Engineering, Python, Technical Documentation Budget: $10 - $30 USD
Traditional Brick Triplex Design Category: Architectural Engineering, Architecture, AutoCAD, Building Architecture, Building Design, Building Engineering, Home Design, Interior Design Budget: $3000 - $5000 USD
22-May-2026 03:45 GMT
3D Fantasy Animation for Kids Event Category: 3D Animation, 3D Design, 3D Modelling, 3D Rendering, Animation, Caricature & Cartoons, Character Illustration, Illustration Budget: $250 - $750 AUD