rake generate can take quite a while, especially when you have many blog posts. Here are a few tips on how to speed up the generation process.

Use rake isolate and rake integrate

It's usually the case when you have many existing posts, while you're modifying a few of them, it's certainly a overkill to compile all the posts if you just ant to preview what you're really editing. Octopress provide an isolate command just for this purpose.

The idea is, you can use rake isolate to move all no-interested posts in an separate directory outside source/_posts , so when you do rake generate, you'll just compile those posts you care about. When you're done editing and want to deploy your sites, you can use rake integrate to move those posts back and generate a complete site.

The usage of rake isolate is simple, you just provide the keywords, and those posts whose title contain these keywords are kept, other posts are moved to source/_stash. Say I'm composing a post named 2013-04-07-hello-world.markdown, and assume this post is the only one that contains hello in its title. Then the following command will do the job:

$ rake isolate[hello]

Use rb-gsl to boost lsi computation

Jekyll has builtin support for related posts, so as Octopress. You just need to add this line to your _config.yml:

lsi: true

Once you enabled lsi, you'll definite want to install rb-gsl package to make the related post generation process faster. When Octopress remind you that:

Notice: for 10x faster LSI support, please install http://rb-gsl.rubyforge.org/

It's not kidding!

Note that Octopress doesn't work with the latest gsl versioned 1.15.*. You'll need to install gsl 1.14 manually since apt or yum will probably install 1.15.* for you.

wget http://ftp.gnu.org/gnu/gsl/gsl-1.14.tar.gz
tar xvf gsl-1.14.tar.gz
cd gsl-1.14
sudo make install

Check the installation by the gsl-config command:

gsl-config --version

Then edit your Gemfile in your blog source root. Add the following line in the development group:

gem 'gsl'

Then use bundle to install it.

bundle install

You're all set. Now when you do rake generate, you shouldn't see that 10x faster line anymore.