Description:
------------
Hello.

Debian 7.11 x64 with nginx.

I am building php7 with this configure options:
./configure --prefix="$PREFIX"\
        --enable-cgi \
        --enable-static \
        \
        --enable-mbstring \
        --enable-soap \
        --enable-zip \
        --enable-calendar\
        --enable-sockets\
        --enable-bcmath\
        \
        --with-zlib\
        --with-openssl=/opt/openssl \
        --with-curl=/opt/curl \
        --with-gettext=shared \
        \
        --with-gd=shared \
        --enable-gd-native-ttf \
        --with-freetype-dir=/usr \
        \
        --with-mcrypt \
        --with-mysqli \
        --with-pdo-mysql \
        \
        --with-jpeg-dir=/usr \
        --with-png-dir=/usr \
        --with-config-file-path="$CFG" \
        --with-config-file-scan-dir="$CFG/conf.d" \
        --enable-fpm



When server backup and disk using
1. If php as CGI - too more PHP CGI process is in uninterruptible sleep with hight LA (50)
2. If php as FPM - too more PHP FPM workers is in uninterruptible sleep with hight LA (50)

PHP-FPM LOG:
[19-Jan-2017 05:22:55] WARNING: [pool avtovokzal] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 48 total children
[19-Jan-2017 05:22:56] WARNING: [pool avtovokzal] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 49 total children
[19-Jan-2017 05:22:57] WARNING: [pool avtovokzal] server reached pm.max_children setting (50), consider raising it

Then I added events.mechanism = epoll to php-fpm.conf the problem solved, but not for CGI.