For public network CLB instances or CLB instances with a static public IP address, Gzip compression is enabled for the HTTP and HTTPS protocols by default. Gzip compresses website files before they are sent to the client browser. This effectively reduces the data volume in network transmission and speeds up webpage loading on the client browser. When using this feature, pay attention to the following:
Must-knows
You must also enable Gzip compression on the backend CVM instances of CLB.
For common Nginx service containers, you must enable Gzip compression in their configuration files (nginx.conf by default) and restart the service.
Currently, CLB supports the following file types. You can use gzip_types to specify the file types for compression.
application/atom+xml application/javascript application/json application/rss+xml application/vnd.ms-fontobject application/x-font-ttf application/x-web-app-manifest+json application/xhtml+xml application/xml font/opentype image/svg+xml image/x-icon text/css text/plain text/x-component;
Note:
You must enable Gzip compression for the above file types in the business software of the backend CVM instances of CLB.
The client requests must carry the compression request identifier.
To enable Gzip compression, the client requests must carry the following identifier:
Accept-Encoding: gzip,deflate,sdch
Example of enabling Gzip compression on CVM instances
Example of CVM runtime environment: Debian 6
1. Use Vim to open the Nginx configuration file in the user path:
vim /etc/nginx/nginx.conf
2. Find the following code:
gzip on;
gzip_min_length 1k;
gzip_buffers 4 16k;
gzip_http_version 1.1;
gzip_comp_level 2;
gzip_types text/html application/json;
Description of the above code syntax:
gzip: specifies whether to enable or disable the Gzip module.
Syntax: gzip on/off
Scopes: http, server, location
gzip_min_length: specifies the minimum number of bytes that a page can be compressed to. The number of bytes can be obtained from Content-Length in the HTTP header. The default value is 1k.
Syntax: gzip_min_length length
Scopes: http, server, location
gzip_buffers: specifies the unit of buffer for storing the data stream of the Gzip compression result. 16k means 16k is used as the unit, and a size of memory that is 4 times the original data size (in 16k) will be applied for.
Syntax: gzip_buffers number size
Scopes: http, server, location
gzip_http_version: specifies the lowest HTTP version that can use Gzip. Value HTTP/1.0 means the lowest HTTP version that needs Gzip is 1.0, so Gzip can be compatible with HTTP/1.1 or higher. You do not need to change the parameter value since Tencent Cloud supports HTTP/1.1 across the entire network.
Syntax: gzip_http_version 1.0 | 1.1;
Scopes: http, server, location
gzip_comp_level: specifies the Gzip compression ratio with a value range of 1–9. Value 1 is the smallest compression ratio with the fastest processing speed, while value 9 is the greatest compression ratio with the slowest processing speed (fast transmission with high CPU consumption).
Syntax: gzip_comp_level 1..9
Scopes: http, server, location
gzip_types: specifies the Multipurpose Internet Mail Extensions (MIME) types for compression. The "text/html" type will be compressed by default. In addition, Gzip for Nginx does not compress static resource files such as JavaScript files and images by default. You can configure gzip_types to specify MIME types to be compressed. Types that are not specified will not be compressed. For example, to compress data in JSON format, you need to add application/json to the parameter value.
The supported types are below:
text/html text/plain text/css application/x-javascript text/javascript application/xml
Syntax: gzip_types mime-type [mime-type ...]
Scopes: http, server, location
3. To modify the configuration, save and exit the file, enter the Nginx bin file directory, and run the following command to reload Nginx:
4. Use the following curl command to test whether Gzip compression is enabled:
curl -I -H "Accept-Encoding: gzip, deflate" "http://cloud.tencent.com/example/"
If a result is returned, Gzip compression is enabled.
If no result is returned, Gzip compression is not enabled.