[Lustre-discuss] Mount error with message: "Err -22 on cfg command:"

[Reto Gantenbein]

Dear Lustre users

Some days ago we had a problem that four OSTs were disconnecting  
themselves. To recover, I deactivated them with 'lctl conf_param  
homefs-OST0002.osc.active=0', remounted them and waited until they  
were recovered and activated them again. Some hosts which kept the  
Lustre file system mounted at this time, resumed to work correctly on  
the paused devices.

But when I want to mount Lustre with on a new client:

node01 ~ # mount -t lustre lustre01 at tcp:lustre02 at tcp:/homefs /home

  it refuses with the following message:

LustreError: 3794:0:(obd_config.c:897:class_process_proc_param())  
homefs-OST0002-osc-ffff81022f630000: unknown param activate=0
LustreError: 3794:0:(obd_config.c:1062:class_config_llog_handler())  
Err -22 on cfg command:
Lustre:    cmd=cf00f 0:homefs-OST0002-osc  1:osc.activate=0
LustreError: 15b-f: MGC10.1.140.1 at tcp: The configuration from log  
'homefs-client' failed (-22). Make sure this client and the MGS are  
running compatible versions of Lustre.
LustreError: 15c-8: MGC10.1.140.1 at tcp: The configuration from log  
'homefs-client' failed (-22). This may be the result of communication  
errors between this node and the MGS, a bad configuration, or other  
errors. See the syslog for more information.
LustreError: 3794:0:(llite_lib.c:1021:ll_fill_super()) Unable to  
process log: -22
LustreError: 3794:0:(mdc_request.c:1273:mdc_precleanup()) client  
import never connected
LustreError: 3794:0:(connection.c:142:ptlrpc_put_connection()) NULL  
connection
Lustre: client ffff81022f630000 umount complete
LustreError: 3794:0:(obd_mount.c:1924:lustre_fill_super()) Unable to  
mount  (-22)

There are no wrong parameters because the same command did work on all  
the previous attempts. Also there is no connection problem between the  
hosts:

lctl > peer_list
12345-10.1.140.1 at tcp [1]node01->lustre01:988 #6
12345-10.1.140.2 at tcp [1]node01->lustre02:988 #6

Why does this cfg command error arise? homefs-OST0002 is properly  
mounted on the lustre-server and is fully working with the other  
clients, as far as I can say. Any hints about this or anything I can  
do to troubleshoot this problem?

Kind regards,
Reto Gantenbein