Working With Rails

I’ve never had an app with that many uploads in such a short period of time. But I may be able to give you a few hints.

For starts: Rails is not really suited for longer tasks – long in this case means actions that take longer than a second or so to process. Each upload blocks one Mongrel until it’s done – so you can have at most 6 concurrent uploads with your application at the moment and users that only want to view your site (and not upload anything) don’t get served at all.

I’ve seen and read a few approaches to deal with that:
- You could use Merb for the upload handling. Merb’s original intent was to speed up file uploads in Rails.
- Using BackgroundRb or some other background processing library may help as well because you can at least take away the resizing/cropping/copying duties from your Mongrels.
- You could define a separate Mongrel cluster that acts as an upload cluster. So you could have, say, 6 Mongrels that only deal with file uploads whereas 2 more Mongrels only serve pages and thus do not block the page for viewers.
- You could also spawn additional Mongrel processes for uploads and terminate them when the upload is finished. This may lower your server’s average load and only give you higher loads in peak times.
- Try Apache and mod_rails.

Regarding your server requirements question: In my experience, a fully busy Mongrel can eat up to 200 MB while it’s doing its job. So assuming that your OS already uses some 100 or 200 MB (I’m not really familiar with BSD), maybe 2 or 3 Mongrels already use swap instead of RAM. I guess the A64 is fine but you should probably give it some more RAM – 4 gig don’t really cost a lot of money nowadays.

HTH (if it does, you could always recommend me ;-))

Hrm, I thought I’d already recommended you. I always, at the very least, give a positive rating. I’ll see what I can do. ;)

As for mod_rails (a.k.a. passenger), I’ve got it installed and I’ve got the following as my ‘passenger.conf’ file:

<VirtualHost *:80>
  ServerName 127.0.0.1 #(I've also tried the public address as there is no domain just yet)
  DocumentRoot /home/git/apps/gittest/public

  ErrorLog /var/log/gittest_errors.log
  CustomLog /var/log/gittest_access.log combined
</VirtualHost>

...however, I am now getting the following error:

Cannot spawn application '/usr/home/git/apps/gittest': The spawn server has exited unexpectedly.

I’m not really sure where to go from here.

Wow! I finally got it. I had a bad reference to ruby. Sheesh! Now passenger is up and running. It seems a bit slower to respond than did “nginx + mongrel”...Is this to be expected? It does, however, have a MUCH smaller memory footprint.

Thanks!

Hrm…one problem I’m still having is the fact that Passenger isn’t picking up my CSS. Is this a permissions issue or what?

And, once again I find the answer buried. ;) I had to add the following:

  <Directory "/home/git/apps/gittest/public"> 
     Options            Indexes FollowSymLinks 
     AllowOverride      None 
     Order              allow,deny 
     Allow              from all 
   </Directory> 

Yeah this stuff with stylesheets was a bitch to find out for me, too. ;) I also had the feeling that it responds a little slower when servicing only one or two requests but as soon as real traffic hits your site it should kick Mongrel in the behind quite good! ;) There’s lots of blog posts out there that confirm that the performance is really great. I’m still running Mongrel in production for now but I think I’ll switch in 2 or 3 months – just have to check with the server admin first. ;)

Ok, so I’ve got everything functioning. Now I need to speed things up severely. The server can handle about 5 to 10 people on, but after that, requests just drag. It’s really as if rails just loses all sense of what it’s supposed to be doing. I don’t think it’s necessarily happening on the request side so much as the DB side (as unlikely as that may sound).

The installation for ruby-prof isn’t very straightforward. I’m told to install it via gems then “copy the ruby package”—but it doesn’t seem to specify what package and from where.

Basically the application is set up to allow the employees to make notes on and categorize Photos as they are uploaded. If there are no photos to be uploaded it sends them to a simple javascript waiting page that refreshes every 10 seconds. Once more photos are up, the process starts again. Once there are more than about 10 people working (and photos present), the application loses its mind. It will do things like place them in a perpetual redirect loop despite the fact that there are clearly Photos available. Sometimes if they log out then log back in they can get back into the real loop, but there’s no guarantee.

If you guys have any suggestions – debug, speed, or otherwise – I’m all ears. I did change the log info to ‘debug’ despite it being in production, but I don’t see anything out of the ordinary. I’m guessing I really need to figure out ruby-prof?

Best,
Michael