Lançou um grande número de processos. Em seguida, reinicie o servidor e o banco de dados desapareceu. Quando entrei no rockmongo, não vi o banco de dados antigo. Houve um novo administrador de banco de dados e nada mais.

 db.serverStatus()
{
        "host" : "host",
        "version" : "2.0.6",
        "process" : "mongod",
        "uptime" : 1041,
        "uptimeEstimate" : 1037,
        "localTime" : ISODate("2012-07-26T08:20:40.729Z"),
        "globalLock" : {
                "totalTime" : 1041408230,
                "lockTime" : 330771,
                "ratio" : 0.0003176189610101314,
                "currentQueue" : {
                        "total" : 0,
                        "readers" : 0,
                        "writers" : 0
                },
                "activeClients" : {
                        "total" : 0,
                        "readers" : 0,
                        "writers" : 0
                }
        },
        "mem" : {
                "bits" : 64,
                "resident" : 19,
                "virtual" : 114,
                "supported" : true,
                "mapped" : 0,
                "mappedWithJournal" : 0
        },
        "connections" : {
                "current" : 11,
                "available" : 808
        },
        "extra_info" : {
                "note" : "fields vary by platform",
                "heap_usage_bytes" : 3623360,
                "page_faults" : 2
        },
        "indexCounters" : {
                "btree" : {
                        "accesses" : 0,
                        "hits" : 0,
                        "misses" : 0,
                        "resets" : 0,
                        "missRatio" : 0
                }
        },
        "backgroundFlushing" : {
                "flushes" : 17,
                "total_ms" : 0,
                "average_ms" : 0,
                "last_ms" : 0,
                "last_finished" : ISODate("2012-07-26T08:20:19.341Z")
        },
        "cursors" : {
                "totalOpen" : 0,
                "clientCursors_size" : 0,
                "timedOut" : 0
        },
        "network" : {
                "bytesIn" : 4429,
                "bytesOut" : 14192,
                "numRequests" : 56
        },
        "opcounters" : {
                "insert" : 0,
                "query" : 22,
                "update" : 0,
                "delete" : 0,
                "getmore" : 0,
                "command" : 54
        },
        "asserts" : {
                "regular" : 0,
                "warning" : 14,
                "msg" : 0,
                "user" : 0,
                "rollovers" : 0
        },
        "writeBacksQueued" : false,
        "dur" : {
                "commits" : 29,
                "journaledMB" : 0,
                "writeToDataFilesMB" : 0,
                "compression" : 0,
                "commitsInWriteLock" : 0,
                "earlyCommits" : 0,
                "timeMs" : {
                        "dt" : 3045,
                        "prepLogBuffer" : 0,
                        "writeToJournal" : 0,
                        "writeToDataFiles" : 0,
                        "remapPrivateView" : 0
                }
        },
        "ok" : 1
}

mongodb.log

    {
            "assertion" : "file /var/lib/mongodb/baza.4 open/create failed in create                                                                             PrivateMap (look in log for more information)",
            "assertionCode" : 13636,
            "errmsg" : "db assertion failure",
            "ok" : 0
    }

Thu Jul 26 12:05:44 [conn5] ERROR: mmap private failed with out of memory. (64 bit build)
Thu Jul 26 12:05:44 [conn5] Assertion: 13636:file /var/lib/mongodb/baza.4 open/create failed in createPrivateMap (look in log for more information)
0x5848a2 0x75dcea 0x75e8e3 0x8a8c3b 0x8a0962 0x8a1d03 0x8a1fda 0x8a2835 0x898619 0x898ea3 0x982bd5 0x97c4f4 0x97dbfd 0x940f05 0x943a30 0x889107 0x88dcd9 0xaa0bc8 0x6389f7 0x2b76122978ca 
 /usr/bin/mongod(_ZN5mongo11msgassertedEiPKc+0x112) [0x5848a2]
 /usr/bin/mongod(_ZN5mongo8MongoMMF13finishOpeningEv+0x1ca) [0x75dcea]
 /usr/bin/mongod(_ZN5mongo8MongoMMF6createESsRyb+0x63) [0x75e8e3]
 /usr/bin/mongod(_ZN5mongo13MongoDataFile4openEPKcib+0x14b) [0x8a8c3b]
 /usr/bin/mongod(_ZN5mongo8Database7getFileEiib+0x102) [0x8a0962]
 /usr/bin/mongod(_ZN5mongo8Database12openAllFilesEv+0x33) [0x8a1d03]
 /usr/bin/mongod(_ZN5mongo8DatabaseC1EPKcRbRKSs+0x1ca) [0x8a1fda]
 /usr/bin/mongod(_ZN5mongo14DatabaseHolder11getOrCreateERKSsS2_Rb+0x605) [0x8a2835]
 /usr/bin/mongod(_ZN5mongo6Client7Context11_finishInitEb+0x2e9) [0x898619]
 /usr/bin/mongod(_ZN5mongo6Client7ContextC1ERKSsSsPNS_9mongolockEb+0x73) [0x898ea3]
 /usr/bin/mongod(_ZN5mongo16CmdListDatabases3runERKSsRNS_7BSONObjEiRSsRNS_14BSONObjBuilderEb+0x215) [0x982bd5]
 /usr/bin/mongod(_ZN5mongo11execCommandEPNS_7CommandERNS_6ClientEiPKcRNS_7BSONObjERNS_14BSONObjBuilderEb+0x6c4) [0x97c4f4]
 /usr/bin/mongod(_ZN5mongo12_runCommandsEPKcRNS_7BSONObjERNS_11_BufBuilderINS_16TrivialAllocatorEEERNS_14BSONObjBuilderEbi+0x6fd) [0x97dbfd]
 /usr/bin/mongod(_ZN5mongo11runCommandsEPKcRNS_7BSONObjERNS_5CurOpERNS_11_BufBuilderINS_16TrivialAllocatorEEERNS_14BSONObjBuilderEbi+0x35) [0x940f05]
 /usr/bin/mongod(_ZN5mongo8runQueryERNS_7MessageERNS_12QueryMessageERNS_5CurOpES1_+0x1740) [0x943a30]
 /usr/bin/mongod() [0x889107]
 /usr/bin/mongod(_ZN5mongo16assembleResponseERNS_7MessageERNS_10DbResponseERKNS_11HostAndPortE+0x559) [0x88dcd9]
 /usr/bin/mongod(_ZN5mongo16MyMessageHandler7processERNS_7MessageEPNS_21AbstractMessagingPortEPNS_9LastErrorE+0x78) [0xaa0bc8]
 /usr/bin/mongod(_ZN5mongo3pms9threadRunEPNS_13MessagingPortE+0x287) [0x6389f7]
 /lib/libpthread.so.0(+0x68ca) [0x2b76122978ca]
Thu Jul 26 12:05:52 [initandlisten] connection accepted from 127.0.0.1:41970 #11

~ # livre -ltm

             total       used       free     shared    buffers     cached
Mem:          1400        196       1203          0          0          0
Low:          1400        196       1203
High:            0          0          0
-/+ buffers/cache:        196       1203
Swap:            0          0          0
Total:        1400        196       1203

~ # cat / proc / sys / vm / overcommit_memory

0

~ # cat / proc / sys / vm / overcommit_ratio

50

~ # ulimit -a

core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 16382
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) unlimited
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

UPD: Solução: desabilite o diário.