logs in one of the nodes

 filestore(/var/lib/ceph/osd/ceph-0) mount FIEMAP ioctl is disabled via 'filestore fiemap' config option
2013-07-22 13:50:27.785944 7f11794e07c0  0 filestore(/var/lib/ceph/osd/ceph-0) mount did NOT detect btrfs
2013-07-22 13:50:27.860013 7f11794e07c0  0 filestore(/var/lib/ceph/osd/ceph-0) mount syncfs(2) syscall fully supported (by glibc and kernel)
2013-07-22 13:50:27.860548 7f11794e07c0  0 filestore(/var/lib/ceph/osd/ceph-0) mount found snaps <>
2013-07-22 13:50:27.875647 7f11794e07c0  0 filestore(/var/lib/ceph/osd/ceph-0) mount: enabling WRITEAHEAD journal mode: btrfs not detected
2013-07-22 13:50:27.895351 7f11794e07c0 -1 journal FileJournal::_open: disabling aio for non-block journal.  Use journal_force_aio to force use of aio anyway
2013-07-22 13:50:27.895426 7f11794e07c0  1 journal _open /var/lib/ceph/osd/ceph-0/journal fd 18: 1073741824 bytes, block size 4096 bytes, directio = 1, aio = 0
2013-07-22 13:50:27.896890 7f11794e07c0 -1 journal FileJournal::open: ondisk fsid 79aa7a52-f48a-4f65-a305-11ec50caeb78 doesn't match expected 0ee464f0-8f19-43bd-9e6c-5564e2f145bf, invalid (someone else's?) journal
2013-07-22 13:50:27.896986 7f11794e07c0 -1 filestore(/var/lib/ceph/osd/ceph-0) mount failed to open journal /var/lib/ceph/osd/ceph-0/journal: (22) Invalid argument
2013-07-22 13:50:27.905853 7f11794e07c0 -1 ^[[0;31m ** ERROR: error converting store /var/lib/ceph/osd/ceph-0: (22) Invalid argument^[[0m