Как разрешить Redis открывать указанное кол-во файлов в Debian 8?

Debian 8

# cat /etc/redis/redis.conf | grep maxclients
maxclients 10000

# cat /etc/default/redis-server
ULIMIT=65536

# cat /etc/sysctl.conf
...
fs.file-max=100000
vm.overcommit_memory = 1

При этом redis-server.log содержит такие строки
[3830] 04 Apr 13:49:24.713 # You requested maxclients of 10000 requiring at least 10032 max file descriptors.
[3830] 04 Apr 13:49:24.713 # Redis can't set maximum open files to 10032 because of OS error: Operation not permitted.
[3830] 04 Apr 13:49:24.713 # Current maximum open files is 1024. maxclients has been reduced to 4064 to compensate for low ulimit. If you need higher maxclients increase 'ulimit -n'.

Как решить эту проблему?