ОС: Windows
Конфиг:

worker_processes 1;
error_log logs/error.log;

events {
accept_mutex off;
}

http {
include mime.types;
default_type application/octet-stream;

log_format main '$remote_addr - $remote_user [$time_local]
$request '
'"$status" $body_bytes_sent "$http_referer" '
'"$http_user_agent" "$http_x_forwarded_for"';

sendfile on;
keepalive_timeout 3;

gzip on;
gzip_min_length 1100;
gzip_buffers 64 8k;
gzip_comp_level 3;
gzip_http_version 1.1;
gzip_proxied any;
gzip_types text/plain application/xml application/x-javascript
text/css;

server {
listen 80;
server_name 21region.org www.21region.org;
access_log logs/access_server.log;
error_log logs/error_server.log;

error_page 403 http://21region.org/error/403.html;
error_page 404 http://21region.org/error/404.html;

# Защита изображений ========================

location ~ \.(bmp|jpg|jpeg|gif|png)$ {
root html/htdocs;
access_log off;
expires 30d;
valid_referers none blocked server_names
forum.21region.org foto.21region.org ~\.google\. images.yandex.ru
doskapozora.ru;
if ($invalid_referer) {
rewrite ^ /hotlinkers.png last;
}
}

location = /hotlinkers.png {
root html/htdocs;
}

# Обновления ============================

location ^~ /avp/ {
alias html/as/avp/;
#access_log logs/antivirus.log;
access_log off;
error_page 403
http://21region.org/error/a403.html;
allow 91.197.172.0/22;
allow 95.81.192.0/19;
allow 89.151.128.0/18;
allow 79.133.128.0/19;
allow 10.0.0.0/8;
allow 172.20.0.0/14;
allow 172.96.0.0/12;
allow 192.168.0.0/16;
allow 91.192.112.0/22;
deny all;
}

location ^~ /drweb/ {
alias html/as/drweb/;
access_log off;
error_page 403
http://21region.org/error/a403.html;
allow 91.197.172.0/22;
allow 95.81.192.0/19;
allow 89.151.128.0/18;
allow 79.133.128.0/19;
allow 10.0.0.0/8;
allow 172.20.0.0/14;
allow 172.96.0.0/12;
allow 192.168.0.0/16;
allow 91.192.112.0/22;
deny all;
}

location ^~ /nod/ {
alias html/as/nod/;
access_log off;
error_page 403
http://21region.org/error/a403.html;
allow 91.197.172.0/22;
allow 95.81.192.0/19;
allow 89.151.128.0/18;
allow 79.133.128.0/19;
allow 10.0.0.0/8;
allow 172.20.0.0/14;
allow 172.96.0.0/12;
allow 192.168.0.0/16;
allow 91.192.112.0/22;
deny all;
}

location ^~ /nod32_3/ {
alias html/as/nod32_3/;
access_log off;
error_page 403
http://21region.org/error/a403.html;
allow 91.197.172.0/22;
allow 95.81.192.0/19;
allow 89.151.128.0/18;
allow 79.133.128.0/19;
allow 10.0.0.0/8;
allow 172.20.0.0/14;
allow 172.96.0.0/12;
allow 192.168.0.0/16;
allow 91.192.112.0/22;
deny all;
}

location ^~ /nod32/ {
alias html/as/nod32/;
access_log off;
index nod27.html;
error_page 403
http://21region.org/error/403.html;
error_page 404
http://21region.org/nod32/nod27.html;
}

# Обновления конец =======================

# Алиасы =================================

location ^~ /userbars/ {
alias html/as/userbars/;
access_log off;
error_page 403
http://21region.org/error/403.html;
error_page 404
http://21region.org/error/404.html;
}

location ^~ /winners/ {
alias html/site/winners/;
access_log off;
error_page 403
http://21region.org/error/403.html;
error_page 404
http://21region.org/error/404.html;
}

location ^~ /history/ {
alias html/site/history/;
access_log off;
error_page 403
http://21region.org/error/403.html;
error_page 404
http://21region.org/error/404.html;
}

location ~ ^/phpmyadmin/.*\.(png|js|jpg)$ {
root html/as;
error_page 403
http://21region.org/error/404.html;
error_page 404
http://21region.org/error/404.html;
access_log logs/access_phpmyadmin.log;
error_log logs/error_phpmyadmin.log;
allow 79.133.128.0/19;
allow 95.81.192.0/19;
allow 195.122.224.0/19;
allow 172.101.12.18;
allow 10.50.16.54;
allow 172.106.0.245;
deny all;
}

# Алиасы конец ==========================

location / {
root html/htdocs;
index index.php;

client_max_body_size 200M;
client_body_buffer_size 16k;

proxy_pass http://127.0.0.1:81;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

deny 87.118.86.0/23;
deny 217.20.116.0/24;
deny 172.101.30.21;
deny 172.101.30.253;
deny 172.101.30.41;
deny 172.20.5.176;
deny 172.21.6.200;

}

location ~*
\.(ico|js|css|txt|swf|flv|mp3|aac|mp4|wmv|avi|mpg|mpeg|mov)$ {
root html/htdocs;
access_log off;
expires 30d;
}

location ~*
\.(doc|pdf|rtf|xls|zip|rar|exe|7z|msi|gz|bz2|iso)$ {
root html/htdocs;
access_log logs/access_download.log;
expires 30d;
}

# Статистика ============================
location = /stat {
stub_status on;
access_log off;
allow all;
deny all;
}
# Статистика конец =======================

}


Проблемма в том, что время от времени сайт перестает реагировать на
запросы.
Если запросить статистику, параметр Writing показывает примерно 245-250.
Через некоторое время параметр уменьшается, и сервер начинает
принимать запросы.
Можно ли как то увеличить этот параметр?
Спасибо.