Support intro
Sorry to hear you’re facing problems. 
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Getting help
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- Official documentation (searchable and regularly updated)
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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. 
The Basics
- Nextcloud Server version (e.g., 29.x.x):
30.0.6
- Operating system and version (e.g., Ubuntu 24.04):
Debian 12 Stable
- Web server and version (e.g, Apache 2.4.25):
Nginx 1.22.1
- Reverse proxy and version _(e.g. nginx 1.27.2)
Nginx 1.22.1
- PHP version (e.g, 8.3):
PHP 8.2
- Is this the first time you’ve seen this error? (Yes / No):
Yes
- Installation method (e.g. AlO, NCP, Bare Metal/Archive, etc.)
Bare Metal/Archive
- Are you using CloudfIare, mod_security, or similar? (Yes / No)
No
Summary of the issue you are facing:
I have 3 Redis servers:
Sentinel: 192.168.1.100:26379
Master: 192.168.1.3:6379
Replica: 192.168.1.4:6379
This is my config.php:
'redis' =>
array (
'host' => '192.168.1.100',
'port' => 26379,
'timeout' => 0.0,
'read_timeout' => 0.0,
'dbindex' => 0,
),
And the Security & setup warnings is showing: Failed to write and read a value from distributed cache. So what’s the proper way to config Redis Sentinel in Nextcloud config?
Configuration
Nextcloud
The output of occ config:list system or similar is best, but, if not possible, the contents of your config.php file from /path/to/nextcloud is fine (make sure to remove any identifiable information!):
'memcache.local' => '\\OC\\Memcache\\APCu',
'memcache.locking' => '\\OC\\Memcache\\Redis',
'memcache.distributed' => '\\OC\\Memcache\\Redis',
'redis' =>
array (
'host' => '192.168.1.100',
'port' => 26379,
'timeout' => 0.0,
'read_timeout' => 0.0,
'dbindex' => 0,
),