I was looking into the code of systemd-journald and found this (in system_journal_open() ) :-
if (!s->system_journal && IN_SET(s->storage, STORAGE_PERSISTENT, STORAGE_AUTO) && (flush_requested || flushed_flag_is_set())) {
/* If in auto mode: first try to create the machine
* path, but not the prefix.
*
* If in persistent mode: create /var/log/journal and
* the machine path */
if (s->storage == STORAGE_PERSISTENT)
(void) mkdir_p("/var/log/journal/", 0755);
(void) mkdir(s->system_storage.path, 0755);
fn = strjoina(s->system_storage.path, "/system.journal");
Here, system_storage.path is set to "strjoin("/var/log/journal/", SERVER_MACHINE_ID(s));" in previous function call.
As far as I understood its saying to create '/var/log/journal' directory when storage is set to 'persistent'.
But in either of the cases (persistent or auto) why is it creating '/var/log/journal/machine_id' directory ( (void) mkdir(s->system_storage.path, 0755); ) ??
'auto' will store logs persistently if '/var/log/journal' is created beforehand or else logs will be written in '/run/log/journal' .
For 'auto' it should not create '/var/log/journal/machine_id' directory right?
Also after reading the comment, how is it possible to create '/var/log/journal/machine_id' without creating the prefix? I am assuming '/var/log/journal' is the prefix .
