Merge branch 'unicorn-advice' into 'master'

Unicorn advice

See merge request !1314

config/unicorn.rb.example

@@ -13,9 +13,9 @@
 #
 # ENV['RAILS_RELATIVE_URL_ROOT'] = "/gitlab"
 
-# Use at least one worker per core if you're on a dedicated server,
-# more will usually help for _short_ waits on databases/caches.
-# The minimum is 2
+# Read about unicorn workers here:
+# http://doc.gitlab.com/ee/install/requirements.html#unicorn-workers
+#
 worker_processes 2
 
 # Since Unicorn is never exposed to outside clients, it does not need to

doc/install/requirements.md

@@ -88,6 +88,16 @@ Sidekiq processes the background jobs with a multithreaded process.
 This process starts with the entire Rails stack (200MB+) but it can grow over time due to memory leaks.
 On a very active server (10,000 active users) the Sidekiq process can use 1GB+ of memory.
 
+## Unicorn Workers
+
+It's possible to increase the amount of unicorn workers.
+This will usually help for short waits on databases and caches.
+
+For most instances we recommend using CPU cores + 1 unicorn workers.
+For a machine with 2 cores, 3 unicorn workers is ideal.
+
+For memory constrained instances, we recommend using a single unicorn worker.
+
 ## Supported web browsers
 
 - Chrome (Latest stable version)