Support intro
Sorry to hear you’re facing problems 
help.nextcloud.com is for home/non-enterprise users. If you’re running a business, paid support can be accessed via portal.nextcloud.com where we can ensure your business keeps running smoothly.
In order to help you as quickly as possible, before clicking Create Topic please provide as much of the below as you can. Feel free to use a pastebin service for logs, otherwise either indent short log examples with four spaces:
example
Or for longer, use three backticks above and below the code snippet:
longer
example
here
Some or all of the below information will be requested if it isn’t supplied; for fastest response please provide as much as you can 
Nextcloud version :14.0.1.1
Operating system and version :openwrt
Apache or nginx version nginx :1.15.3
PHP version :7.2.9
The issue you are facing:
When I download a file (including online play), the hard disk will continue to be in the read data state. It seems that the complete reading of a file will stop, even if the connection has been disconnected. This is for fast switching files. In the case, especially when large files are used, the performance of the server will be seriously slowed down. Is there any way to solve it?
Is this the first time you’ve seen this error? :N
The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):
<?php
$CONFIG = array (
'instanceid' => 'xxxxx',
'passwordsalt' => 'xxxxx',
'secret' => 'xxxxx',
'trusted_domains' =>
array (
0 => 'xxxxx',
),
'datadirectory' => 'xxxxx',
'dbtype' => 'mysql',
'version' => '14.0.1.1',
'overwrite.cli.url' =>'xxxxx',
'dbname' => 'xxxxx',
'dbhost' => 'localhost',
'dbport' => '',
'dbtableprefix' => 'oc_',
'mysql.utf8mb4' => true,
'dbuser' => 'xxxxx',
'dbpassword' => 'xxxxx',
'installed' => true,
'mail_smtpmode' => 'smtp',
'mail_smtpauthtype' => 'LOGIN',
'memcache.local' => '\\OC\\Memcache\\APCu',
'updater.secret' => 'xxxxx',
'maintenance' => false,
'theme' => '',
'loglevel' => 2,
);