Problem setting up multi-level directory sessions in php

Find session.save_path in php.ini and set the value to session.save_path = '3;/tmp/session'; to enable the third-level directory to save the session. However, php will not automatically generate the directory structure. At this time, you can use mod_files.sh in the ext/session directory of the source code package to generate the directory

$ bash mod_files.sh /tmp/session 3

After the generation is completed, it is found that the session still cannot be generated. After struggling for a long time, I discovered the mystery when I opened mod_files.bat. It turns out that I need to bring a parameter later, which corresponds to session.hash_bits_per_character in php.ini. This value defaults to 4, and the default configuration of the development and production versions is 5, so I use The following command regenerates the directory

$ bash mod_files.sh /tmp/session 3 5

Finally you can log in.