# Cache large static files in memory **URL:** \ **Category:** NGINX\ **Created:** [June 24, 2009, 7:10am UTC](https://www.ruby-forum.com/t/cache-large-static-files-in-memory/170936 "2009-06-24T07:10:13Z")\ **Posts on this page:** 9\ **Page:** 1
**Author:** ![Hua\_Su](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/b9bd4f/32.png) [@Hua\_Su](https://www.ruby-forum.com/u/Hua_Su)\ **Post date:** [June 24, 2009, 7:10am UTC](https://www.ruby-forum.com/t/cache-large-static-files-in-memory/170936/1 "2009-06-24T07:10:13Z")
Hi all,Does nginx support to cache static files in memory if it finds several large files are requested frequently? If yes, how to control the cache? If not, is there any simple way to implement a similar function? ---
**Author:** ![Hua\_Su](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/b9bd4f/32.png) [@Hua\_Su](https://www.ruby-forum.com/u/Hua_Su)\ **Post date:** [June 24, 2009, 8:02am UTC](https://www.ruby-forum.com/t/cache-large-static-files-in-memory/170936/2 "2009-06-24T08:02:21Z")
The linux file system will cache recently or frequently used files in memory regardless, and the effect is similar in performance to an application level cache. A separate application level cache would not necessarily be desirable since the file system cache would largely have the same items in it anyway; storing them again in an application level memory cache would simply leave less total memory available to file caching or other uses. ---
**Author:** ![Hua\_Su](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/b9bd4f/32.png) [@Hua\_Su](https://www.ruby-forum.com/u/Hua_Su)\ **Post date:** [June 24, 2009, 8:27am UTC](https://www.ruby-forum.com/t/cache-large-static-files-in-memory/170936/3 "2009-06-24T08:27:32Z")
Thanks! So is there any guidance about how to configure cache behavior of linux file systems to gain max performance? ---
**Author:** ![Hua\_Su](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/b9bd4f/32.png) [@Hua\_Su](https://www.ruby-forum.com/u/Hua_Su)\ **Post date:** [June 24, 2009, 1:02pm UTC](https://www.ruby-forum.com/t/cache-large-static-files-in-memory/170936/4 "2009-06-24T13:02:02Z")
It’s noticed that Apache provides MMapFile directives in mod\_file\_cache, which allows you to have Apache map a static file’s contents into memory at start time (using the mmap system call). Apache will use the in-memory contents for all subsequent accesses to this file. Does NginX have similar module or configuration options? ---
**Author:** ![Hua\_Su](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/b9bd4f/32.png) [@Hua\_Su](https://www.ruby-forum.com/u/Hua_Su)\ **Post date:** [June 24, 2009, 9:52am UTC](https://www.ruby-forum.com/t/cache-large-static-files-in-memory/170936/5 "2009-06-24T09:52:32Z")
I’m not exactly sure. Generally it works pretty well if you’ve got enough spare ram compared to the size of the files that need to be in the cache. There is a tendency to only buy as much ram for your server as you need to avoid swapping, but if you add a couple more gigs you can improve your i/o performance pretty significantly. That’s also pretty cheap with ram prices so low these days. ---
**Author:** ![Hua\_Su](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/b9bd4f/32.png) [@Hua\_Su](https://www.ruby-forum.com/u/Hua_Su)\ **Post date:** [June 26, 2009, 5:56pm UTC](https://www.ruby-forum.com/t/cache-large-static-files-in-memory/170936/6 "2009-06-26T17:56:30Z")
## hua Wrote: > It’s noticed that Apache provides MMapFile directives in mod\_file\_cache, which allows you to have Apache > map a static file’s contents into memory at start time (using the mmap system call). > Apache will use the in-memory contents for all subsequent accesses to this file. > Does NginX have similar module or configuration options? mmap syscall doesn’t mean file loaded into memory. It means that application can read/write file as memory, and two or more processes can share access to this file without allocating memory and load file into each other. eNGINeX doesn’t need this feature, because it is FSM, and not read file at once, it read file piece by piece so fast as peer can receive. In this case best give OS to manage cache and files. > > > Thanks! So is there any guidance about how to > > > configure cache behavior > > > of linux file systems to gain max > > > performance? > > > This is offtopic, try google if you want to find answers 🙂 Posted at Nginx Forum: > **[Re: cache large static files in memory](https://forum.nginx.org/read.php?2,3316,3398#msg-3398)** > > Hi all,Does nginx support to cache static files in memory if it finds several large files are requested frequently? If yes, how to control the cache? If not, is there any simple way to implement a similar function? -- Hua Su ---
**Author:** ![Hua\_Su](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/b9bd4f/32.png) [@Hua\_Su](https://www.ruby-forum.com/u/Hua_Su)\ **Post date:** [May 24, 2011, 6:54pm UTC](https://www.ruby-forum.com/t/cache-large-static-files-in-memory/170936/7 "2011-05-24T18:54:01Z")
openvz uses conteiner virtualization. The memory is shared with other vm’s. The configuration of yourvz.conf show how much is your guaranteed memory, and bursted memory. And its not possible add a swap disk using swapon to a file image. Em 24/05/2011, s 10:31, drmetal escreveu: ---
**Author:** ![Hua\_Su](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/b9bd4f/32.png) [@Hua\_Su](https://www.ruby-forum.com/u/Hua_Su)\ **Post date:** [May 24, 2011, 3:32pm UTC](https://www.ruby-forum.com/t/cache-large-static-files-in-memory/170936/8 "2011-05-24T15:32:22Z")
Hello, does this (linux RAM cache) apply to OpenVZ machines (Guests)? Because when I run free -m command, i see 0 in buffers and cached. Anyone knows how that goes in OpenVZ? Thanks Posted at Nginx Forum: > **[Re: cache large static files in memory](https://forum.nginx.org/read.php?2,3316,200352#msg-200352)** > > Hi all,Does nginx support to cache static files in memory if it finds several large files are requested frequently? If yes, how to control the cache? If not, is there any simple way to implement a similar function? -- Hua Su ---
**Author:** ![Hua\_Su](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/h/b9bd4f/32.png) [@Hua\_Su](https://www.ruby-forum.com/u/Hua_Su)\ **Post date:** [May 24, 2011, 11:14pm UTC](https://www.ruby-forum.com/t/cache-large-static-files-in-memory/170936/9 "2011-05-24T23:14:27Z")
Thanks for the answer but this doesn’t answer my question. Obviously I have shared RAM. My question was, does linux store frequently used files in RAM ? Because this is usually reported in the free -m command output. But in the case of OpenVZ VPS I see nothing (0) in the cached and buffers column. I researched a little, the system caches files, they are just not reported. ## Felipe aka lpr Wrote: > Em 24/05/2011, às 10:31, drmetal escreveu: > > > > > * * * > > nginx mailing list > removed\_email\_address@domain.invalid > [nginx Info Page](http://nginx.org/mailman/listinfo/nginx) Posted at Nginx Forum: > **[Re: cache large static files in memory](https://forum.nginx.org/read.php?2,3316,200528#msg-200528)** > > Hi all,Does nginx support to cache static files in memory if it finds several large files are requested frequently? If yes, how to control the cache? If not, is there any simple way to implement a similar function? -- Hua Su