[HPDD-discuss] can not mount file system after upgrade from 1.8.8 to 2.5.3

Evening We have a slight disaster on our hands :( After upgrading from 1.8.8 to 2.5.3 we can no longer mount some of our MDTs. With 1.8.8 we had set atime_diff via lctl and now 2.5.3 can't mount the file system cause it doesn't know about atime_diff Feb 14 22:32:41 mds0004 kernel: LustreError: 5607:0:(obd_config.c:1341:class_process_proc_param()) mdt: p4-MDT0000 unknown param atime_diff=86400 I tried tunefs.lustre --erase-params /dev/md2 which "worked" but didn't solve the problem. The issue is that we set the parameter with lctl, which has put the config into CONFIGS/p4-MDT0000 from hexdump 000049a0 6d 64 74 2e 61 74 69 6d 65 5f 64 69 66 66 00 00 |mdt.atime_diff..| which is NOT touched by tunefs.lustre--erase-params . Is the only option to mount this mdt using 1.8.8 and then wipe the parameter with lctl and then try the upgrade again? Or should I just go in with an hex editor and set the string to 00 00 00 etc...?? Thanks. -- Dr Stuart Midgley sdm900(a)sdm900.com