udev read only file system 70-persistent-net.rules

Hello, i made a fresh install of proxmox 4.2 ISO on a supermicro server, motherboard X9DR7-TF+. Here is, in /var/log/syslog : May 16 10:52:12 prox03 udev-finish[1374]: /lib/udev/udev-finish: 6: /lib/udev/udev-finish: cannot create /etc/udev/rules.d/70-persistent-net.rules: Read-only file system...