Windows Edition: Server 2012 R2 Standard (with most recent updates) Processor: Intel(R) Xeon(R) CPU E5-2620 v3 @ 2.40GHz (2 processors) System type: 64-bit OS, x64-basd processor
In IIS, I have 1 FTP site that is publicly accessible, 5 websites that are publicly accessible, and 1 website that is accessible only on the server (via 127.0.0.1). The 6 websites are all running with ColdFusion as the server software. Each website runs in its own Application Pool.
Four of the public websites read and write data to and from an external IBM DB2 database. The other public website reads and writes data to and from a local SQL Server database.
The problem: At random times, any one of the websites will suddenly become inaccessible, responding with a 503 HTTP Status Code. When this happens, all the other websites are up and running fine. Executing "iisreset" in Command Prompt always resolves the issue.
These websites are not heavily trafficked. In fact, sometimes an outage will happen in the middle of the night when there is next to no traffic. I can't for the life of me figure how or why this is happening. I need some help with where to look and what to look for in order to permanently resolve this.