Hello,
Many thanks to Bruno Leveque and Tom Lane for your sharp answers :
> You forgot to give the new /tmp directory the correct permissions.
> The right on /tmp must be : drwxrwxrwt and owner : root, group : root
My permissions were false
drwxr-xr-x
chmod 1777 /tmp
restored the right ones
drwxrwxrwt 6 root root 1024 déc 19 10:56 tmp
postgresql starts, xfs also and certainly a lot of other problems are avoided
Cheers
Patrice