All MGS/MDT/OSTs running CentOS 5.4 x86_64 2.6.18-92.1.26.el5_lustre.1.6.7.2smp A few weeks ago I had added an OST (OST000c) incorrectly. I set it as inactive by: lctl --device 17 deactivate and lctl conf_param webcache-OST000c.osc.active=0 No data was ever written to it, so no harm done. I then reformatted the OST properly and added it (OST000d) to the lustre successfully. The volume ran great. I have a few more OSTs on a new OSS to add to the volume. The came from another newer lustre array (v1.8.1.1) that we were "downsizing" so I removed the 1.8.1.1 lustre RPMs and installed the v1.6.7.2 RPMs and rebooted. I then reformatted the OSTs like this: mkfs.lustre -v --reformat --fsname webcache --ost --mgsnode=webcache-mds01 at tcp /dev/sdb and mkfs.lustre -v --reformat --fsname webcache --ost --mgsnode=webcache-mds01 at tcp /dev/sdc I mounted them up, but the volume size did not increase. After checking the MDS I found something weird. Here''s a ''lctl dl'' on the MGS: [root at webcache-mds01 ~]# lctl dl 0 UP mgs MGS MGS 124 1 UP mgc MGC10.4.20.1 at tcp 0dbf20ab-e2af-2170-ee62-3c92fc63b2a7 5 2 UP mdt MDS MDS_uuid 3 3 UP lov webcache-mdtlov webcache-mdtlov_UUID 4 4 UP mds webcache-MDT0000 webcache-MDT0000_UUID 245 5 UP osc webcache-OST0000-osc webcache-mdtlov_UUID 5 6 UP osc webcache-OST0001-osc webcache-mdtlov_UUID 5 7 UP osc webcache-OST0002-osc webcache-mdtlov_UUID 5 8 UP osc webcache-OST0003-osc webcache-mdtlov_UUID 5 9 UP osc webcache-OST0004-osc webcache-mdtlov_UUID 5 10 UP osc webcache-OST0005-osc webcache-mdtlov_UUID 5 11 UP osc webcache-OST0006-osc webcache-mdtlov_UUID 5 12 UP osc webcache-OST0007-osc webcache-mdtlov_UUID 5 13 UP osc webcache-OST0008-osc webcache-mdtlov_UUID 5 14 UP osc webcache-OST0009-osc webcache-mdtlov_UUID 5 15 UP osc webcache-OST000a-osc webcache-mdtlov_UUID 5 16 UP osc webcache-OST000b-osc webcache-mdtlov_UUID 5 17 UP osc webcache-OST000c-osc webcache-mdtlov_UUID 5 18 UP osc webcache-OST000d-osc webcache-mdtlov_UUID 5 19 UP osc webcache-OST000e-osc webcache-OST000c-osc-mdtlov_UUID 4 20 UP osc webcache-OST000f-osc webcache-OST000c-osc-mdtlov_UUID 4 Why do the 2 new OST have "webcache-OST000c-osc-mdtlov_UUID 4" instead of "webcache-mdtlov_UUID 5" after the OSC name? When I mounted the 2 new OSTs the syslog on the MDS shows: Mar 29 22:35:07 webcache-mds01 kernel: LustreError: 1377:0:(obd_config.c:836:class_process_config()) no device for: webcache-OST000c-osc-mdtlov Mar 29 22:35:07 webcache-mds01 kernel: LustreError: 1377:0:(obd_config.c:1102:class_config_llog_handler()) Err -22 on cfg command: Mar 29 22:35:07 webcache-mds01 kernel: Lustre: cmd=cf00d 0:webcache-OST000c-osc-mdtlov 1:webcache-OST000e_UUID 2:14 3:1 Mar 29 22:36:49 webcache-mds01 kernel: LustreError: 1384:0:(obd_config.c:836:class_process_config()) no device for: webcache-OST000c-osc-mdtlov Mar 29 22:36:49 webcache-mds01 kernel: LustreError: 1384:0:(obd_config.c:1102:class_config_llog_handler()) Err -22 on cfg command: Mar 29 22:36:49 webcache-mds01 kernel: Lustre: cmd=cf00d 0:webcache-OST000c-osc-mdtlov 1:webcache-OST000f_UUID 2:15 3:1 Something is right and I''m not sure where to start digging. Thoughts? Thanks, Scott Barber Senior Systems Administrator iMemories.com