把server_names_hash_bucket_size改大点即可，可以改成64或128试下，放在http {}里

Syntax:	server_names_hash_bucket_size size;
Default:	server_names_hash_bucket_size 32|64|128;
Context:	http

Sets the bucket size for the server names hash tables. The default value depends on the size of the processor’s cache line. The details of setting up hash tables are provided in a separate document.