Static file benchmarks

Denis S. Filimonov den.lists at
Sat Apr 19 00:10:41 MSD 2008

On Friday 18 April 2008 15:47:11 Cocoa Guy wrote:
> On Fri, Apr 18, 2008 at 11:23 AM, kingler <kingler at> wrote:
> > It appears that you are using the Amazon EC2 Small Instance (default):
> >  Note that it says "I/O Performance: Moderate" in the description of
> >  small instance.
> >
> >  Maybe you are hitting the bottleneck of the disk IO...
> Yes, the numbers I posted are for the small instance. Unfortunately I
> tried a Large instance and got the same numbers (but the OS remained
> the same 32 bit OS)
> On Fri, Apr 18, 2008 at 11:38 AM, Denis S. Filimonov
> <den.lists at> wrote:
> > Amazon EC2 works in a virtualized environment with a network filesystem.
> >  It's hard to expect top performance in such setting.
> >  It's also hard to tell which factors limit the throughput because you
> > don't get to see the full picture.
> Right, this is a virtualized environment, but the disk performance on
> an EC2 instance is at least 40 MB/sec. Is it possible at that speed
> for the disk to be the limiting factor? I've read that files read from
> disk are cached in the kernel cache, but I have no clue...
The problem is probably the latency rather than raw disk read throughput.
For example, in NFS, every time a process opens a file, a request is sent to 
the NFS server to check if the file has changed, even though the file itself 
can be locally cached. This is done to implement so called close-to-open 

If this is the case (I'm not even sure what filesystem they use) then using 
NGINX's file descriptor cache *might* help. Sadly, it is described in the 
wiki, yet. Try adding the following snippet:
open_file_cache          max=1000  inactive=20s;
open_file_cache_valid    30s;
open_file_cache_min_uses 2;
open_file_cache_errors   on;


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