Use number_to_human_size for system info and remove dependency on Filesize gem.

Gemfile

@@ -349,4 +349,3 @@ gem 'health_check', '~> 1.5.1'
 
 # System information
 gem 'vmstat', '~> 2.1.0'
-gem 'filesize', '~> 0.1.1'

Gemfile.lock

@@ -207,7 +207,6 @@ GEM
       multi_json
     ffaker (2.0.0)
     ffi (1.9.10)
-    filesize (0.1.1)
     flay (2.6.1)
       ruby_parser (~> 3.0)
       sexp_processor (~> 4.0)
@@ -851,7 +850,6 @@ DEPENDENCIES
   email_spec (~> 1.6.0)
   factory_girl_rails (~> 4.6.0)
   ffaker (~> 2.0.0)
-  filesize (~> 0.1.1)
   flay
   flog
   fog-aws (~> 0.9)

app/controllers/admin/system_info_controller.rb

@@ -3,10 +3,10 @@ class Admin::SystemInfoController < Admin::ApplicationController
     system_info = Vmstat.snapshot
     @load = system_info.load_average.collect { |v| v.round(2) }.join(', ')
 
-    @mem_used = Filesize.from("#{system_info.memory.active_bytes} B").to_f('GB').round
-    @mem_total = Filesize.from("#{system_info.memory.total_bytes} B").to_f('GB').round
+    @mem_used = system_info.memory.active_bytes
+    @mem_total = system_info.memory.total_bytes
 
-    @disk_used = Filesize.from("#{system_info.disks[0].used_bytes} B").to_f('GB').round
-    @disk_total = Filesize.from("#{system_info.disks[0].total_bytes} B").to_f('GB').round
+    @disk_used = system_info.disks[0].used_bytes
+    @disk_total = system_info.disks[0].total_bytes
   end
 end

app/views/admin/system_info/show.html.haml

@@ -14,9 +14,9 @@
       .light-well
         %h4 Memory
         .data
-          %h1= "#{@mem_used}GB / #{@mem_total}GB"
+          %h1= "#{number_to_human_size(@mem_used)} / #{number_to_human_size(@mem_total)}"
     .col-sm-4
       .light-well
         %h4 Disk
         .data
-          %h1= "#{@disk_used}GB / #{@disk_total}GB"
+          %h1= "#{number_to_human_size(@disk_used)} / #{number_to_human_size(@disk_total)}"

app/views/layouts/nav/_admin.html.haml

@@ -10,7 +10,7 @@
         %span
           Overview
     = nav_link(controller: %w(system_info background_jobs logs health_check)) do
-      = link_to admin_background_jobs_path, title: 'Monitoring' do
+      = link_to admin_system_info_path, title: 'Monitoring' do
         %span
           Monitoring
     = nav_link(controller: :broadcast_messages) do