Nginx large static file running slower on an AWS EBS-enabled server

I am trying to figure out the correct configuration for nginx on an AWS server fully supported by EBS. The main problem is that when loading a static file of 100 MB in size, I observe consistent download speeds of ~ 60 K / s. If I use scp to copy the same file from the AWS server, I see a speed of ~ 1 MB / s. (So, I'm not sure if EBS even comes into play here).

Initially, I started nginx mainly from a ready-made configuration (for CentOS 6.x). But, trying to speed up the work, I played with various settings to no avail - the speed remained basically the same.

Here is the corresponding snippet from my configuration, as it stands at the moment:

location /download {
    root /var/www/yada/update;
    disable_symlinks off;
    autoindex  on;

    # Transfer tuning follows
    aio        on;
    directio   4m;
    output_buffers 1 128k;
}

Initially, these settings were as follows:

sendfile       on;
tcp_nopush     on;
tcp_nodelay    on;

, . , - . AWS - "" 617 . , scp ~ 1 /, , HTTP .

.

[] . "top" , :

top - 07:37:33 up 11 days,  1:56,  1 user,  load average: 0.00, 0.01, 0.05
Tasks:  63 total,   1 running,  62 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.0%us,  0.0%sy,  0.0%ni,100.0%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st

'iostat' :

Linux 3.2.38-5.48.amzn1.x86_64      04/03/2013  _x86_64_    (1 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           0.02    0.00    0.03    0.03    0.02   99.89

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
xvdap1            0.23         2.66         8.59    2544324    8224920