Tuesday, April 26, 2011

FireFox 4 Scaling Well

There is always a period of time after you requisition hardware that you are a little nervous about performance. Very happy to report that Firefox is scaling very well and we have jumped over the magic number of 100 concurrent users in FF.

The only open issue right now in regards to Firefox is that it still is having an occasional oddity in regards to NFS. From watching patterns, it seems like if you are downloading a big (1GB+) file and writing it over NFS, the server get's sluggish. It never comes to a crawl, but has a noticeable slowdown. I was able to make this work better by downgrading from NFS4 to NFS3. I'll see if I can figure it out and submit a proper bug report.

The shots below are 100 concurrent FF sessions. Not everyone is surfing at the same time, but it still shows the memory usage along with CPU for maybe 30ish active sessions. Very happy to see Flash not multi-threading. :) I believe this server could easily handle another 100 users, and can easily be upgraded in terms of RAM.


Anonymous said...

Careful with the blurring there; you can still pretty easily make out some of the usernames you've blurred. Also, various research has shown that most blurring algorithms prove relatively easy to semi-reverse to make text readable again. We have few enough unique letters in English that it doesn't take much to reliably distinguish them. Put a solid color over stuff you actually want to hide. :)

Anonymous said...

A few recommendations to improve resource usage even further:

You can adjust Firefox's in-memory cache size, as well as the size of the cache of back/forward pages. Keep the latter around and the former becomes nearly unnecessary.

Install Adblock Plus and configure it systemwide. That will end up blocking a huge number of Flash ads, which means far less simultaneous usage of Flash.

Install a local caching proxy on the server, configure Firefox to use it, and then massively turn down Firefox's disk cache. Then you get one big shared cache across users.

Anonymous said...

Also, don't forget to run a local caching DNS server.

Dave Richards said...

@anonymous: Understand about blur. What's ironic is that users complain about spam and then gladly put their email addresses openly right on our web site :)

@anonymous: Proxy server in place and working well. I need to spend some time adjusting the various settings to try and find the sweet spot. Right now FF is fast. Unfortunately I can't do any FlashBlock globally because we have found a few sites that it won't play correctly once you click on the play button. But I'll come back to this issue again.

@anonymous: A local DNS server is on our radar too. Right now we are impacted by the speed of the public DNS servers for sure. It's always an issue of $$, staff resources and hours of the day.

Anonymous said...

I hadn't thought about FlashBlock; I don't have any experience with it. I specifically meant Adblock Plus, to block ads (flash and otherwise) entirely. That doesn't affect other uses of Flash.

Anonymous said...

The unbound cache DNS server is easy to setup and works very well =).