I installed the latest 2.5.3 version on the latest CentOS 6.5 version with all upgrades and used the following commands to create a lustre file system:

1. Created /etc/modprobe.d/lustre.conf

options lnet networks=tcp0(eth0)

2. Started lnet

service lnet start

lctl net up

3. Created MGS and MDT:

mkfs.lustre --mgs /dev/sdb

mkfs.lustre --mdt --mgsnode=1.1.1.125@tcp0 --network=tcp0 --fsname=fs01 --index=0 /dev/sdc

4. Updated /etc/ldev.conf

mgs - MGS /dev/sdb -

mgs - fs01:MDT0000 /dev/sdc -

5. Started Lustre:

service lustre start MGS

service lustre start fs01:MDT0000

6. And getting the following error:

Sep 18 12:29:03 localhost kernel: LustreError: 11-0: fs01-MDT0000-lwp-MDT0000: Communicating with 0@lo, operation mds_connect failed with -11.

I checked that lctl ping 0@lo is working properly.