With Update to 27.1.2 i tried at once the switch back to redis-server.sock instead the tcp:port connection to redis.
I switched back my settings as seen above but same login problem / session handler problem.
So i changed the following things:
a) in nextcloud/config/config.php i set
'redis' =>
array (
'host' => '/var/run/redis/redis-server.sock',
'port' => 0,
),
b) in php/8.2/fpm/php.ini i set
[Session]
; Handler used to store/retrieve data.
; https://php.net/session.save-handler
#session.save_handler = files
session.save_handler = redis
#session.save_path = "tcp://127.0.0.1:6379?weight=1&database=10"
#-> alternatively see: https://github.com/phpredis/phpredis#php-session-handler
session.save_path = "unix:///var/run/redis/redis-server.sock?persistent=1&weight=1&database=0"
redis.session.locking_enabled = 1
redis.session.lock_retries = -1
redis.session.lock_wait_time = 10000
instead of just /var/run/redis...
. i changed the line to
"unix:///var/run/redis/redis-server.sock?persistent=1&weight=1&database=0"
as described here
https://github.com/phpredis/phpredis#php-session-handler
In some posts in the www concerning redis.sock / unix sock communication an advice for
setting unix perm to 777 instead of 770 - but this wasn’t nescessary in my case.
(/etc/redis/redis.conf)
After a reboot of the whole server i was able to login again as expected with using redis-server.sock for phpsessions as well.
Maybe my investigations help others - running crazy to find what’s going wrong - in similar cases.