Context: http, server, and location
Defines the number and size of larger buffers to be used for storing client requests, in the event the default buffer (client_header_buffer_size) was insufficient. Each line of the header must fit in the size of a single buffer. If the request URI line is greater than the size of a single buffer, Nginx returns the 414 Request URI too large error. If another header line exceeds the size of a single buffer, Nginx returns a 400 Bad request error.
Syntax: large_client_header_buffers amount size
Default value: 4*8 kilobytes