IS servers can be configured to fail-over to alternate servers for requests which involve a source image which cannot be opened or read successfully.
The following types of requests are redirected:
IS Images that are in the catalog, but not on disk.
If an image is not in a catalog, error redirect should not happen when the image can’t be found.
Corrupt images, color profiles, or fonts.
Static content can’t be found on disk.
Static content requests are redirected when it can’t be found on disk, even if the referenced static content does not have a catalog record.
Error redirect does not happen in any other case.
When enabled and when such an error occurs during the processing of the request, the primary server sends the request to the secondary server for processing. The response, regardless of whether it indicates success or failure, is then forwarded directly to the client. The primary server marks log entries of such forwarded requests with cache use
REMOTE. The response data is not cached locally by the primary server.
Error redirect is enabled by setting
PS::errorRedirect.rootUrl to the HTTP domain name and port number of the secondary server. In addition, the connection timeout is configured with
PS::errorRedirect.connectTimeout and the maximum time the primary server waits for a response from the secondary server before returning an error to the client is configured with
If the secondary server cannot be contacted, a text error response is returned to the client, even if a default image or error image is configured.
Pipe characters (|) in the net path are not supported for error redirection.