How do you handle bandwidth billing on shared servers in apache? - linux

Question

What solutions do you have in place for handling bandwidth billing for your vhosts on a shared environment in apache? If you are using log parsing, does your solution scale well when the logs become very very large? Anyone using any sort of module out there for this?

Answer 1

There exist certain modules for Apache 1.x and 2.x that will allow you to set a maximum on the transfer amount, most of them keep track using the scoreboard file that Apache generates (when mod_status is enabled with ExtendedStatus on). The one I still have bookmarked from when I was looking for one is mod_curb, however it is not complete and at the current moment in time looks to only work on a server-wide scale and not for individual virtual hosts.
Apache modules can be set to be outbound filters, so you could write a costume module that would sit at the end of the chain, and add up all the outgoing packets, using the data that APR provides you can then add it to a counter for that specific domain/sub-domain. After that you have a choice of what to do with the data.
For specific examples, take a look at mod_deflate that Apache provides, to see how it sits at the end of the chain and compresses everything but the headers the server sends out. This should give you a good start.
As for log based processing, it becomes slower the more logs exist. This is just the nature of the beast. When we were using a log based solution we had a custom perl script that ran every 15 minutes. Eventually it would take longer than 15 minutes to parse, and since we had proper locking after a while multiple of these log processing perl scripts were now running, all waiting on each other. We ended up re-writing it with a simple call to tail -F, which then let perl parse each and every request as it came in, while not entirely efficient, it worked. The upside of that was that we were now able to update traffic statistics in near realtime so that clients were updated sooner rather than later if they went over their limits.

Answer 2

You could go the poor man's route, and use Webalizer or Awstats. Both of these will give you an idea of traffic based off of access logs, and can be done on a per virtual host basis. In the case of Awstats, I know once you start doing 10GB+ of traffic daily, it starts to consume resources. You can always nice it, but then you'll get your data next week, rather than when you actually need it. In the past with Webalizer I've had to use some hackery to get it to handle large access logs, by chunking up the logs to smaller pieces that it could manage. It didn't provide as many useful metrics from what I've done with it, but I've also never needed to save a server from it :)

Answer 3

If virtual host does not have own IP, there is no easier way than logfile parsing. Just use mod_logio to calculate actual bytes transferred. mod_logio handles broken connections, compressed data etc. correctly. You should be able to parse logs realtime using piped logs. Use BufferedLogs to scale further (just check that parser handles lines broken when buffered correctly). Parser should save data periodically (like every minute) somewhere, just avoid locking issues as parsing must not slow down httpd. If httpd connections is spending time in L-state at server-status, you are too slow. After you have numbers, you can sum then further and then save data to billing system.
If you save billing logs as file too you can correct and doublecheck realtime traffic calculations. If you boot httpd you can end up missing some lines. But generally losing couple hundred requests is acceptable as it less than seconds worth on a high volume site.
There is modules that try to handle and limit bandwidth, like mod_cband and mod_bw. But they don't work when you have same vhost on multiple machines. I guess they would work ok on smaller scale.
If you have IP per vhost you could try IP based methods like feeding firewall logs to traffic calculator. Simple way is to use iptables.

Answer 4

Although we use IIS rather than apache we do use log file analysis for bandwidth billing (and bandwidth profiling / analysis). We use a custom application to load data collected in the log files in one hour increments, and act upon any required notifications or bandwidth overuse.
The log file loader runs as a low priority process, so as not to interupt operation of the server. Even on high usage servers with a large number of sites, processing takes less than 15 minutes, so we don't see scalability as a problem with this methodology.
There may be better ways of doing this, but this is perfectly adequate for what we need. I look forward to viewing the other responses.

Answer 5

It can be easily achieved with mod_cband. We've rewritten the module to fix a few bugs, provide true redundancy on restarts and incorporate FTP and Mail statistics.
http://www.howtoforge.com/mod_cband_apache2_bandwidth_quota_throttling

Answer 6

Well mod_cband would be great, except for when i'm using it, the max_connections (the overall, total value for every client combined), decides to crawl upwards until it hits the max value i've set. when it does reach the highest value, it just stays there and leaves all my clients receiving a constant "503 Service Temporarily Unavailable" error.
for example, i set "CbandSpeed 1000Mbps 500 1200", and the server connections crawls up to 1200 in about 8 hrs, then stays there. at this point, i count the total number of connections under Remote Clients in the mod_cband status window, and i see around 50. i've also used ps aux and i see around the same amount (~50) open http processes, which is normal, except for the fact that nobody can access the site at all because of the 503 errors.
Any ideas what could be wrong, or can this be fixed?