kernel: sd 1:0:0:0: reservation conflict

Hi,
I have a problem about Red Hat Cluster, it detected cluster services failure and then it restarted services automatically. Error message as the following:
Feb 16 10:06:22 kcsandnp01 kernel: sd 1:0:0:0: reservation conflict
Feb 16 10:06:22 kcsandnp01 kernel: sd 1:0:0:0: [sdb] Result: hostbyte=DID_OK driverbyte=DRIVER_OK
Feb 16 10:06:22 kcsandnp01 kernel: sd 1:0:0:0: [sdb] CDB: Write(10): 2a 00 00 0e 25 3f 00 00 08 00
Feb 16 10:06:22 kcsandnp01 kernel: end_request: critical nexus error, dev sdb, sector 927039

Please kindly help.

Thank you very much.
Thirat S.