# Page/action caching across multiple machines **URL:** \ **Category:** Deployment\ **Created:** [March 25, 2008, 2:46pm UTC](https://www.ruby-forum.com/t/page-action-caching-across-multiple-machines/132877 "2008-03-25T14:46:10Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![jeff](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jeff](https://www.ruby-forum.com/u/jeff)\ **Post date:** [March 25, 2008, 2:46pm UTC](https://www.ruby-forum.com/t/page-action-caching-across-multiple-machines/132877/1 "2008-03-25T14:46:10Z")
Does anyone have a preferred way of doing page/action caching across multiple machines? I know with fragment caching you can use memcached. But page caching usually goes in the document root, so it is not usually in a shared directory. I saw one suggestion which was to change the page cache directory to / public/cache, and then modify the Apache re-write rules to check for static content in /public first, and then /public/cache second. But that seems klunky. Another crazy idea I heard was to possibly NFS/GFS mount the entire application directory, and then your second application machine has everything shared with the first one. (Only PID file locations would need to be kept separate.) Does anyone have any experience or preferred methods on this? There is suprisingly little documentation on scaling Rails to multiple boxes. thanks, Jeff co-founder, cto > **[PatientsLikeMe](https://www.patientslikeme.com/?format=html)** > > The world’s largest personalized health network that helps people find new treatments, connect with others and take action to improve their outcomes. ---
**Author:** ![jeff](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jeff](https://www.ruby-forum.com/u/jeff)\ **Post date:** [March 25, 2008, 8:22pm UTC](https://www.ruby-forum.com/t/page-action-caching-across-multiple-machines/132877/2 "2008-03-25T20:22:28Z")
On Mar 25, 2008, at 6:45 AM, Jeff wrote: > Jeff > > co-founder, cto > [www.patientslikeme.com](http://www.patientslikeme.com) We use GFS to share a /data partition between multiple servers. The rails apps and assets + page caches are available in a consistent way across multiple boxes this way. It works very well. GFS has context dependant symlinks so you can have private directories for pid and log files on each machine even though they all write to the same path. I must warn you that getting GFS and red hat cluster suite setup and working properly is a battle though and took us a long time to get completely stable, in the end it’s totally worth it though. Another option if you don’t have a SAN is to use memcached for your page caches and use the memcached module in nginx so nginx will hit memcached first for cached pages and if the cache misses it will fall back to your rails app which serves the page and stores it in memcached. You use the uri for the memcached key. This is much easier to setup than GFS, but GFS performs much better than memcached for page cached pages in our test. On one of our larger clients clusters we are able to get 25kreq/sec for a GFS page cache and only 8kreq/sec for a memcached page cache. Still both perform very well so it’s just a matter of how much time you want to spend getting things set up. Of course all engineyard slices come with GFS and SAN storage 😉 Cheers- - Ezra Z. – Founder & Software Architect – removed\_email\_address@domain.invalid – [EngineYard.com](http://EngineYard.com) ---
**Author:** ![jeff](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jeff](https://www.ruby-forum.com/u/jeff)\ **Post date:** [March 26, 2008, 8:34pm UTC](https://www.ruby-forum.com/t/page-action-caching-across-multiple-machines/132877/3 "2008-03-26T20:34:17Z")
On Mar 26, 2008, at 7:23 AM, Jeff wrote: > Thanks for the reply, Ezra. We actually have an NFS mount set up, but > I’ve read your warnings against NFS, so I’d like to try memcached. > The only kicker is we are running Apache, which I know how to change > the Rewrite rules to look for static content on the mount first, but > not sure how to do that with Apache + memcached. This may be the > excuse I’ve been looking for to dump Apache, anyway. > > thanks again for the help, > jeff Hey Jeff- It’s a great excuse to dump apache 😉 But before you do that take a look at this module: [http://tangent.org/608/mod\_memcached.html](http://tangent.org/608/mod_memcached.html) I have not used this and I don’t know much about it but it can probably do the same thing nginx mod\_memcached can do I would imagine. In case you decide to try nginx let me save you a little time with the magic memcached config options: Say you have all page caches in /article location /article { ``` proxy_intercept_errors on; default_type text/html; charset UTF-8; if ($request_method = GET) { # Say nginx to try to fetch some key from memcache: # serve with correct mime type and charset set $memcached_key "app-production:article:$uri"; memcached_pass memcached_cluster; # If no info would be found in memcache or memecache would be ``` dead, go to # /fallback location error\_page 404 502 504 = @fallback; break; } ``` if (!-f $request_filename) { proxy_pass http://mongrels; break; } ``` } location @fallback { proxy\_set\_header Host $http\_host; proxy\_set\_header X-Real-IP $remote\_addr; proxy\_set\_header X-Forwarded-For $proxy\_add\_x\_forwarded\_for; proxy\_redirect false; proxy\_max\_temp\_file\_size 0; # Pass request to mongrel proxy\_pass [http://mongrels](http://mongrels); } Cheers- - Ezra Z. – Founder & Software Architect – removed\_email\_address@domain.invalid – [EngineYard.com](http://EngineYard.com) ---
**Author:** ![jeff](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/e19b73/32.png) [@jeff](https://www.ruby-forum.com/u/jeff)\ **Post date:** [March 26, 2008, 3:24pm UTC](https://www.ruby-forum.com/t/page-action-caching-across-multiple-machines/132877/4 "2008-03-26T15:24:36Z")
Thanks for the reply, Ezra. We actually have an NFS mount set up, but I’ve read your warnings against NFS, so I’d like to try memcached. The only kicker is we are running Apache, which I know how to change the Rewrite rules to look for static content on the mount first, but not sure how to do that with Apache + memcached. This may be the excuse I’ve been looking for to dump Apache, anyway. thanks again for the help, jeff