Greg Marr wrote: > At 01:41 PM 10/27/2006, Davi Arnaut wrote: >> Niklas Edmundsson wrote: >>> And when you have a file backend, you want to hit your disk cache >> and >>> not the backend when delivering data to a client. People might >> think >>> that this doesn't matter, but for large files, especially larger >> than >>> RAM in your machine, you usually go disk-bound without much help >> from >>> the OS disk cache. >> But that's a corner case. There is no reason in doing this for small >> files (common case). For example, in a enterprise grade server >> memory is >> cheap and permanent storage is slow and expensive. > > So why would this server be using mod_disk_cache in that > case? Shouldn't this server be using mod_mem_cache? Selecting > mod_disk_cache over mod_mem_cache means it's better to serve the > cache from disk rather than from memory. If serving from the disk on > the original request is too slow, then wouldn't serving from the disk > on the subsequent requests be too slow as well? >
Because the data is already in memory. Why should I write something to disk, erase it from memory, and read it again shortly ? Why should I take care of something that is the job of the OS ? Why should I trash the VM constantly ? A proxy/cache common purpose is to cache web content, this means we have a large number of small files (think html pages, images, etc) that we must keep in a permanent storage, but if we have memory, let's use it! -- Davi Arnaut
