Warning: PDO::__construct(): Error An operation on a socket could not be performed because the syst (trying to connect via tcp://DBSERV:3306)

Sorry for the long title.

This is an error message I'm receiving on a Windows Server 2008 R2. I am receiving this message in the logs of both a Magento installation, and Drupal 7 just before the sites go down.

I run two boxes in this setup. One web server that runs both IIS 7 and Apache 2.2.16, and a separate DB server that runs both SQL Server 2008, and Mysql 5.1.49

I've Google'd this message, and it looks like it is generated by a Windows specific error code: 10055, that indicates a resource problem. The only solutions I'm finding though relate to older versions of Windows, or 32-bit versions of Windows:

http://blogs.msdn.com/b/sql_protocols/archive/2009/03/09/understanding-the-error-an-operation-on-a-socket-could-not-be-performed-because-the-system-lacked-sufficient-buffer-space-or-because-a-queue-was-full.aspx

Neither of which is the case here, so the suggested fixes don't apply.

I'm not seeing much of anything in the Event logs, and I'm stuck as to where to go next to troubleshoot this. One other message that's maybe of some importance is just before I get the socket errors, I start receiving this error from Magento:

Warning: 开发者_如何学Csimplexml_load_string(): Memory allocation failed : growing buffer

Anyone have any ideas?

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It's most certainly a resources issue. It looks like Magento is doing something which is trying to CONSUME ALL THE MEMORY :) to the point that socket operations start to fail. Start by examining what it's trying to load with simplexml_load_string.