$ mongodump --host xxxx --username xxxx --password xxx --collection xxx --db xxxx
connected to: prodmongoperf-a.lan.flt
DATABASE: locos_production       to     dump/locos_production
        locos_production.conversations.user_history.encounters to dump/locos_production/conversations.user_history.encounters.bson
                12800/3595618   0%
                32100/3595618   0%
                50600/3595618   1%
^[              69000/3595618   1%
                86400/3595618   2%
                103900/3595618  2%
                127200/3595618  3%
                144700/3595618  4%
                162200/3595618  4%
                179700/3595618  4%
                197200/3595618  5%
                214700/3595618  5%
                238000/3595618  6%
                255400/3595618  7%
                278800/3595618  7%
                290400/3595618  8%
                302100/3595618  8%
Tue Nov 15 16:23:21 Assertion: 13273:single data buffer expected
0x81b22f5 0x820fa68 0x8211c58 0x81ef9f8 0x81f007f 0x8707709 0x8708293 0x870c470 0x870e738 0x8701231 0x8706c99 0xb7447bd6 0x8128e91
 mongodump(_ZN5mongo11msgassertedEiPKc+0x145) [0x81b22f5]
 mongodump(_ZN5mongo14DBClientCursor12dataReceivedERbRSs+0x198) [0x820fa68]
 mongodump(_ZN5mongo14DBClientCursor18exhaustReceiveMoreEv+0x178) [0x8211c58]
 mongodump(_ZN5mongo18DBClientConnection5queryEN5boost8functionIFvRNS_27DBClientCursorBatchIteratorEEEERKSsNS_5QueryEPKNS_7BSONObjEi+0x1d8) [0x81ef9f8]
 mongodump(_ZN5mongo18DBClientConnection5queryEN5boost8functionIFvRKNS_7BSONObjEEEERKSsNS_5QueryEPS4_i+0x43f) [0x81f007f]
 mongodump(_ZN4Dump12doCollectionESsP8_IO_FILEPN5mongo13ProgressMeterE+0x459) [0x8707709]
 mongodump(_ZN4Dump19writeCollectionFileESsN5boost10filesystem10basic_pathISsNS1_11path_traitsEEE+0x1b3) [0x8708293]
 mongodump(_ZN4Dump2goESsN5boost10filesystem10basic_pathISsNS1_11path_traitsEEE+0x480) [0x870c470]
 mongodump(_ZN4Dump3runEv+0x1b38) [0x870e738]
 mongodump(_ZN5mongo4Tool4mainEiPPc+0x1631) [0x8701231]
 mongodump(main+0x59) [0x8706c99]
 /lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe6) [0xb7447bd6]
 mongodump() [0x8128e91]
assertion: 13273 single data buffer expected
Tue Nov 15 16:23:21 Socket flush send() errno:9 Bad file descriptor 10.130.161.82:27017
Tue Nov 15 16:23:21   caught exception (socket exception) in destructor (~PiggyBackData)