Hi, My lustre environment is: 2.6.9-55.0.9.EL_lustre.1.6.3smp One of my OSS''s crashed today. Below you can see messages sent by it (storage09) to the syslog (first three lines). Then it died (my guess is with kernel panic) and heartbeat software STONITH that OSS''s. Nov 9 19:08:44 storage09.beowulf.cluster kernel: LDISKFS-fs error (device dm-5): mb_free_blocks: double-free of inode 38887437''s block 155560192(bit 10496 in group 4747) Nov 9 19:08:44 storage09.beowulf.cluster kernel: Nov 9 19:08:44 storage09.beowulf.cluster kernel: Remounting filesystem read-only Nov 9 19:08:44 storage09.beowulf.cluster kernel: LDISKFS-fs error (device dm-5): mb_free_blocks: double-free of inode 38887437''s block 155560193(bit 10497 in group 4747) Nov 9 19:09:13 storage10.beowulf.cluster heartbeat: [21231]: WARN: node storage09: is dead Nov 9 19:09:13 storage10.beowulf.cluster heartbeat: [21231]: info: Link storage09:eth0 dead. Nov 9 19:09:13 storage10.beowulf.cluster heartbeat: [21231]: info: Link storage09:eth2 dead. Nov 9 19:09:13 storage10.beowulf.cluster heartbeat: [32414]: info: Resetting node storage09 with [external/ipmi ] Do you know how serious are LDISKFS-fs errors? Is that indicates data corruption on the certain block device? Device dm-5 is a DDN LUN. DDN controller S2A9500 says that everything is Healthy there. Cheers Wojciech Turek