PostgreSQL: changing data directory location (sshfs)

Question

I'm trying to change my PostgreSQL data directory initially on my Debian server to my NAS (running also on linux). To do so, I've mounted it on a specific directory through sshfs (in /mnt/titanBDD).

Now I get this error when starting postgre (using service and pg_ctlcluster):

Error: could not exec /usr/lib/postgresql/9.4/bin/pg_ctl /usr/lib/postgresql/9.4/bin/pg_ctl start -D /var/lib/postgresql/9.4/redirect_TITAN -l /var/log/postgresql/postgresql-9.4-main.log -s -o -c config_file="/etc/postgresql/9.4/main/postgresql.conf"

Here is the modified part of postgresql.conf:

data_directory = '/var/lib/postgresql/9.4/main'

modified in:

data_directory = '/var/lib/postgresql/9.4/redirect_TITAN'

Where redirect_TITAN:

0 lrwxrwxrwx 1 root root 18 nov.   1 16:23 /var/lib/postgresql/9.4/redirect_TITAN -> /mnt/titanBDD/main

I've used the following command to move my data:

root@machine:~# cp --preserve=all -R /var/lib/postgresql/9.4/main/ /mnt/titanBDD/

Acutally, in /mnt/titanBDD I have:

root@machine:~# ls -als /mnt/titanBDD/
total 12
4 drwxr-xr-x 1 postgres postgres 4096 nov.   1 16:19 .
4 drwxr-xr-x 3 root     root     4096 nov.   1 14:05 ..
4 drwx------ 1 postgres postgres 4096 nov.   1 15:59 main

What is going wrong? I guess it's a context issue but don't have any idea where to search.

Answer 1

I finally solved the problem using -o allow_other when mounting the /mnt/titanBDD with sshfs.

The error message was still :

Error: could not exec

/usr/lib/postgresql/9.4/bin/pg_ctl /usr/lib/postgresql/9.4/bin/pg_ctl 
start -D /var/lib/postgresql/9.4/redirect_TITAN
-l /var/log/postgresql/postgresql-9.4-main.log -s -o -c
config_file="/etc/postgresql/9.4/main/postgresql.conf"

(which repeat the command twice?!)

when executing:

usr/lib/postgresql/9.4/bin/pg_ctl 
start -D /var/lib/postgresql/9.4/redirect_TITAN
-l /var/log/postgresql/postgresql-9.4-main.log -s -o -c
config_file="/etc/postgresql/9.4/main/postgresql.conf"

but I noticed the user postgres didn't have access to the mounted point which put me on the track.

Now PostgreSQL starts without any problem.