Php+iis Prompt Service Unavailable

How to configure today, PHP configuration on the prompt on the page prompts the Service unavailable, natural, ASP also can not run normally, and later in IIS to check the configuration of PHP, Found that the Php5isapi.dll is not loaded by the ISAPI filter, is a red downward arrow, the normal situation should be the green up arrow, indicating the success of the load! Then you remove it and restart IIS, and the results page appears normal! So check the configuration of PHP, also did not find anything unusual, and finally thought that there might be permission issues, so check the permissions of the PHP installation folder, found no Everyone permissions, I do not know when the Everyone permissions to delete, So the new to everyone with read-only permission (read-only permission is sufficient), after restarting IIS, everything is OK

A description of the service unavailable the site appears

Reason one: The Web site exceeds the number of IIS connections

Solution One: Increase the number of IIS connections

Note: Windows 2003 's operating system does not prompt IIS too much, as the Win2000 system prompts "too many links", but rather prompts "Service unavailable"

Reason two: The Web site exceeds the IIS resource limit

Solution Two: Increase the resources of the website

Note Two: Winodws2003 the Web site occupies more than IIS restrictions on the site system resources directly prompted the "Service unavailable"

Reason three: The website's program has too many errors

Workaround Three: Modify program errors

Note Three: There are too many site errors in Winodws2003, which can cause an error in the application pool where the site is located, at which point "application pool ' xxx" is automatically disabled in the Windows2003 log, due to a series of errors in the process of servicing the application pool. This time the website will show "Service unavailable" directly.

The above three causes of "Service Unavailable", the general phenomenon is "service Unavailable" after more than a few refresh, you can open.

Reason four: Access engine error

Workaround Four: Restart IIS

Note IV: Some files caused the Access database to have a "catastrophic failure" and "no object references set to an instance of an object" error

Cause four causes "Service unavailable", the phenomenon is that all Web sites that use Access databases on this server have errors and cannot be accessed.

The above four reasons are common cause of "Service unavailable" reasons, and some other problems caused the problem, basically as long as the IIS restart can be.

Sometimes the application pool limit is IIS6.0, and in IIS management you can see application pool management, point attributes, and limit the memory size so that the pool is automatically recycled. This balances server resources and does not appear "Service unavailable