last little bit of log:
2013-04-24 10:38:53.906498 7f99a1ffb700 10 mon.a@0(probing) e1 sync_start entity( mon.2 10.214.131.27:6790/0 )
2013-04-24 10:38:54.082770 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )).monmap v1 get_monmap ver 0
2013-04-24 10:38:54.113164 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )) e1 sync_store_init backup current monmap
2013-04-24 10:38:54.132404 7f99a1ffb700 1 -- 10.214.131.27:6789/0 --> mon.2 10.214.131.27:6790/0 -- mon_sync( start ) v1 -- ?+0 0x7f9988332770
2013-04-24 10:38:54.132466 7f99a1ffb700 1 -- 10.214.131.27:6789/0 <== mon.1 10.214.131.28:6789/0 26693 ==== forward(osd_alive(want up_thru 1693 have 1693) v1) to leader v1 ==== 292+0+0 (2477513207 0 0) 0x7f995801c040 con 0x1483700
2013-04-24 10:38:54.132477 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 have connection
2013-04-24 10:38:54.132483 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 ms_dispatch existing session MonSession: mon.1 10.214.131.28:6789/0 is openallow * for mon.1 10.214.131.28:6789/0
2013-04-24 10:38:54.132489 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 caps allow *
2013-04-24 10:38:54.132491 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )) e1 received forwarded message from osd.1 10.214.131.27:6807/9377 via mon.1 10.214.131.28:6789/0
2013-04-24 10:38:54.132500 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )) e1 mesg 0x7f995801ead0 from 10.214.131.28:6789/0
2013-04-24 10:38:54.132504 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 have connection
2013-04-24 10:38:54.132506 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 ms_dispatch existing session MonSession: osd.1 :/0 is openallow * for osd.1 :/0
2013-04-24 10:38:54.132509 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 caps allow *
2013-04-24 10:38:54.132512 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )).paxosservice(osdmap) dispatch osd_alive(want up_thru 1693 have 1693) v1 from osd.1 10.214.131.27:6807/9377
2013-04-24 10:38:54.159939 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )).paxosservice(osdmap) waiting for paxos -> readable (v1693)
2013-04-24 10:38:54.159988 7f99a1ffb700 1 -- 10.214.131.27:6789/0 <== mon.2 10.214.131.27:6790/0 25940 ==== forward(osd_pgtemp(e1691 {1.c=[5,1],1.10=[5,1],1.13=[5,1],1.15=[5,1],1.16=[5,1],1.17=[5,1],2.b=[5,1],2.c=[5,1],2.f=[5,1],2.12=[5,1],2.14=[5,1],2.15=[5,1],2.16=[5,1],3.a=[1,5],3.b=[1,5],3.e=[5,1],3.24=[1,5],3
.28=[1,5],3.2c=[5,1],3.33=[1,5],3.46=[1,5],3.47=[1,5],3.49=[1,5],3.4f=[1,5],3.55=[5,1],3.5c=[5,1],3.69=[5,1],3.6a=[1,5],3.70=[1,5],3.7b=[5,1],3.7d=[5,1],3.81=[5,1],3.85=[1,5],3.8e=[1,5],3.93=[1,5],3.94=[1,5],3.96=[1,5],3.a6=[5,1],3.a7=[1,5],3.ac=[1,5],3.ad=[1,5],3.b1=[1,5],3.b3=[5,1],3.b8=[1,5],3.b9=[1,5],3.bd=[1,5
],3.bf=[1,5],3.c5=[1,5],3.c8=[5,1],3.d3=[1,5],3.d9=[1,5],3.dc=[5,1],3.dd=[5,1],3.e9=[5,1],3.ea=[1,5],3.f0=[1,5]} v1691) v1) to leader v1 ==== 1920+0+0 (2818135077 0 0) 0x7f994010cc60 con 0x147eed0
2013-04-24 10:38:54.160039 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 have connection
2013-04-24 10:38:54.160043 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 ms_dispatch existing session MonSession: mon.2 10.214.131.27:6790/0 is openallow * for mon.2 10.214.131.27:6790/0
2013-04-24 10:38:54.160050 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 caps allow *
2013-04-24 10:38:54.160052 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )) e1 received forwarded message from osd.5 10.214.131.28:6801/3534 via mon.2 10.214.131.27:6790/0
2013-04-24 10:38:54.160061 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )) e1 mesg 0x7f994010cf90 from 10.214.131.27:6790/0
2013-04-24 10:38:54.160065 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 have connection
2013-04-24 10:38:54.160067 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 ms_dispatch existing session MonSession: osd.5 :/0 is openallow * for osd.5 :/0
2013-04-24 10:38:54.160070 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 caps allow *
2013-04-24 10:38:54.160072 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )).paxosservice(osdmap) dispatch osd_pgtemp(e1691 {1.c=[5,1],1.10=[5,1],1.13=[5,1],1.15=[5,1],1.16=[5,1],1.17=[5,1],2.b=[5,1],2.c=[5,1],2.f=[5,1],2.12=[5,1],2.14=[5,1],2.15=[5,1],2.16=[5,1],3.a=[1,5],3.b=[1,5],3.e=[5,1],3.2
4=[1,5],3.28=[1,5],3.2c=[5,1],3.33=[1,5],3.46=[1,5],3.47=[1,5],3.49=[1,5],3.4f=[1,5],3.55=[5,1],3.5c=[5,1],3.69=[5,1],3.6a=[1,5],3.70=[1,5],3.7b=[5,1],3.7d=[5,1],3.81=[5,1],3.85=[1,5],3.8e=[1,5],3.93=[1,5],3.94=[1,5],3.96=[1,5],3.a6=[5,1],3.a7=[1,5],3.ac=[1,5],3.ad=[1,5],3.b1=[1,5],3.b3=[5,1],3.b8=[1,5],3.b9=[1,5],
3.bd=[1,5],3.bf=[1,5],3.c5=[1,5],3.c8=[5,1],3.d3=[1,5],3.d9=[1,5],3.dc=[5,1],3.dd=[5,1],3.e9=[5,1],3.ea=[1,5],3.f0=[1,5]} v1691) v1 from osd.5 10.214.131.28:6801/3534
2013-04-24 10:38:54.187198 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )).paxosservice(osdmap) waiting for paxos -> readable (v1691)
2013-04-24 10:38:54.187244 7f99a1ffb700 1 -- 10.214.131.27:6789/0 <== osd.3 10.214.131.28:6807/2695 25 ==== mon_subscribe({monmap=2+,osd_pg_creates=0,osdmap=1690}) v2 ==== 69+0+0 (4248948145 0 0) 0x7f9944001000 con 0x7f9994003340
2013-04-24 10:38:54.187262 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 have connection
2013-04-24 10:38:54.187266 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 ms_dispatch existing session MonSession: osd.3 10.214.131.28:6807/2695 is openallow * for osd.3 10.214.131.28:6807/2695
2013-04-24 10:38:54.187273 7f99a1ffb700 20 mon.a@0(synchronizing sync( requester state start )) e1 caps allow *
2013-04-24 10:38:54.187276 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )) e1 handle_subscribe mon_subscribe({monmap=2+,osd_pg_creates=0,osdmap=1690}) v2
2013-04-24 10:38:54.187282 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )) e1 check_sub monmap next 2 have 1
2013-04-24 10:38:54.187291 7f99a1ffb700 5 mon.a@0(synchronizing sync( requester state start )).osd e1693 send_incremental [1690..1693] to osd.3 10.214.131.28:6807/2695
2013-04-24 10:38:54.217461 7f99a1ffb700 10 mon.a@0(synchronizing sync( requester state start )).osd e1693 build_incremental [1690..1693]
2013-04-24 10:38:54.324263 7f99a1ffb700 -1 mon/OSDMonitor.cc: In function 'MOSDMap* OSDMonitor::build_incremental(epoch_t, epoch_t)' thread 7f99a1ffb700 time 2013-04-24 10:38:54.305016
mon/OSDMonitor.cc: 1475: FAILED assert(0)
ceph version 0.60-641-gc7a0477 (c7a0477bad6bfbec4ef325295ca0489ec1977926)
1: (OSDMonitor::build_incremental(unsigned int, unsigned int)+0x12e3) [0x4f96e3]
2: (OSDMonitor::send_incremental(unsigned int, entity_inst_t&, bool)+0x1a8) [0x4f9908]
3: (OSDMonitor::check_sub(Subscription*)+0xa0) [0x4f9cd0]
4: (Monitor::handle_subscribe(MMonSubscribe*)+0x9dd) [0x4a7edd]
5: (Monitor::_ms_dispatch(Message*)+0x10e3) [0x4c21a3]
6: (Monitor::ms_dispatch(Message*)+0x32) [0x4d8e12]
7: (DispatchQueue::entry()+0x3f1) [0x6aec41]
8: (DispatchQueue::DispatchThread::entry()+0xd) [0x63cbad]
9: (()+0x7e9a) [0x7f99aa654e9a]
10: (clone()+0x6d) [0x7f99a8e71cbd]
NOTE: a copy of the executable, or `objdump -rdS <executable>` is needed to interpret this.