Moving or deleting files never responds, causes PHP to time out

Nextcloud version (eg, 18.0.2): 18.0.7
Operating system and version (eg, Ubuntu 20.04): Debian 10.4
Apache or nginx version (eg, Apache 2.4.25): Apache 2.4.38
PHP version (eg, 7.1): 7.3.20-1+0~20200710.65+debian10~1.gbpc9cbeb

The issue you are facing:

Moving or deleting a file never completes. The processing icon just spins forever. The HTTP request is dispatched but no response ever arrives.
E.g. DELETE https://cloud.internal.example.com/remote.php/dav/files/1d07a501-605f11e8-8c77c862-0c77e7f2/Everyone/Readme.md

Often the only way to continue working is to forcibly restart the server’s PHP-FPM service, service php7.3-fpm restart.

Is this the first time you’ve seen this error? (Y/N): N

Steps to replicate it:

  1. Try to delete or move a file.

The output of your Nextcloud log in Admin > Logging:
There are no new log entries when attempting the file actions.

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):

<?php
$CONFIG = array (
  'instanceid' => 'ocs6pbp54s7p',
  'passwordsalt' => '',
  'secret' => '',
  'trusted_domains' =>
  array (
    0 => 'cloud.internal.example.com',
  ),
  'datadirectory' => '/var/www/cloud/data',
  'dbtype' => 'mysql',
  'version' => '18.0.7.1',
  'overwrite.cli.url' => 'https://cloud.internal.example.com',
  'installed' => true,
  'maintenance' => false,
  'dbname' => 'cloud_nextcloud',
  'dbhost' => 'db.internal.example.com',
  'dbuser' => 'cloud',
  'dbpassword' => '',
  'mail_smtpmode' => 'sendmail',
  'mail_sendmailmode' => 'smtp',
  'mail_from_address' => 'cloud',
  'mail_domain' => 'internal.example.com',
  'ldapIgnoreNamingRules' => false,
  'ldapProviderFactory' => 'OCA\\User_LDAP\\LDAPProviderFactory',
  'theme' => '',
  'loglevel' => 2,
  'mysql.utf8mb4' => true,
);

The output of your Apache/nginx/system log in /var/log/____:

Apache access log /var/log/apache2/cloud.internal.example.com.access.log shows a 504 (gateway timeout):

***::11 - - [19/Jul/2020:13:44:37 +0200] "DELETE /remote.php/dav/files/1d07a501-605f11e8-8c77c862-0c77e7f2/Everyone/Re$dme.md HTTP/1.1" 504 864 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.89 $afari/537.36"

Apache error log /var/log/apache2/cloud.internal.example.com.error.log shows timeout talking with FastCGI:

[Sun Jul 19 13:44:53.478764 2020] [proxy_fcgi:error] [pid 12218] (70007)The timeout specified has expired: [client ***::11:52178] AH01075: Error dispatching request to : (polling)

/var/log/php7.3-fpm.log shows nothing special:

[19-Jul-2020 13:27:54] NOTICE: fpm is running, pid 3486
[19-Jul-2020 13:27:54] NOTICE: ready to handle connections
[19-Jul-2020 13:27:54] NOTICE: systemd monitor interval set to 10000ms
(Nothing further)

Looks like it happens when trying to unshare too, and renaming a file or folder.
This is terrible.