How can I measure my (SAMP) server's bandwidth usage?

Question

I'm running a Solaris server to serve PHP through Apache. What tools can I use to measure the bandwidth my server is currently using? I use Google analytics to measure traffic, but as far as I know, it ignores file size. I have a rough idea of the average size of the pages I serve, and can do a back-of-the-envelope calculation of my bandwidth usage by multiplying page views (from Google) by average page size, but I'm looking for a solution that is more rigorous and exact.

Also, I'm not trying to throttle anything, or implement usage caps or anything like that. I'd just like to measure the bandwidth usage, so I know what it is.

An example of what I'm after is the usage meter that Slicehost provides in their admin website for their users. They tell me (for another site I run) how much bandwidth I've used each month and also divide the usage for uploading and downloading. So, it seems like this data can be measured, and I'd like to be able to do it myself.

To put it simply, what is the conventional method for measuring the bandwidth usage of my server?

Answer 1

I am just guessing, but I think the usual approach is to use the same tools and services that are used to deliver QoS features. QoS == Quality of Service. Somewhere on the server itself, or on the network routers around the server, there will be services enabled that measure the size of the packets flowing out of your server. These same services can be used to limit the amount of bandwidth for customers that need to have such limitations enforced. I have not heard of an application that can be run on your server that measures bandwidth. I think it should be possible to create such an app, but that's not the usual way that such measurements are collected. I suspect this answer will end up not being solaris-specific.

Answer 2

This depends on your setup. If you have a (near-)dedicated physical interface for your web server you could gather stats straight from the interface.

Methods to do this could include SNMP (try net-snmp) or "ifconfig", combined with RRDTool or simple logging to flat files.

An alternative is using the Apache log, which could look like this:

192.168.101.155 - - [17/Apr/2005:20:39:19 -0700] "GET / HTTP/1.1" 200 1456
192.168.101.155 - - [17/Apr/2005:20:39:19 -0700] "GET /apache_pb.gif HTTP/1.1" 200 2326
192.168.101.155 - - [17/Apr/2005:20:39:19 -0700] "GET /favicon.ico HTTP/1.1" 404 303
192.168.101.155 - - [17/Apr/2005:20:39:42 -0700] "GET /index.html.ca HTTP/1.1" 200 1663
192.168.101.155 - - [17/Apr/2005:20:39:42 -0700] "GET /apache_pb.gif HTTP/1.1" 304 -
192.168.101.155 - - [17/Apr/2005:20:39:43 -0700] "GET /favicon.ico HTTP/1.1" 404 303
192.168.101.155 - - [17/Apr/2005:20:40:01 -0700] "GET /apache_pb.gif HTTP/1.1" 304 -
192.168.101.155 - - [17/Apr/2005:20:40:09 -0700] "GET /apache_pb.gift HTTP/1.1" 404 306
192.168.101.155 - - [17/Apr/2005:20:40:09 -0700] "GET /favicon.ico HTTP/1.1" 404 303

The last number is the amount of bytes transferred, excluding the header(!). See Apache Log Docs.