Re: modproxy load balancer
Bill Stoddard <[email protected]> Tue, 08 Jul 2003 10:39:39 -0400
| Newsgroups | gmane.comp.apache.mod-proxy |
|---|---|
| Message-ID | <[email protected]> |
Perhaps I am being silly, but do we need to standardize on a definition of 'downstream' and 'upstream'? Here is a comment from proxy_http.c: /* Note: Memory pool allocation. * A downstream keepalive connection is always connected to the existence * (or not) of an upstream keepalive connection. If this is not done then * load balancing against multiple backend servers breaks (one backend * server ends up taking 100% of the load), and the risk is run of * downstream keepalive connections being kept open unnecessarily. This * keeps webservers busy and ties up resources. * * As a result, we allocate all sockets out of the upstream connection * pool, and when we want to reuse a socket, we check first whether the * connection ID of the current upstream connection is the same as that * of the connection when the socket was opened. */ If I am reading this correctly, my polarity must be different that the author of this comment. The way I look at it, most bytes flow from the webserver to the web client. Analogous to water, the bytes flow 'downstream' from the server to the client. Now a proxy maintains two connections, one to the client and one to the webserver. I would call the connection from the client to the proxy the 'downstream' connection and the connection from the proxy to the server the 'upstream' connection. What say you? Bill