Critical - P2 ISSUE SUMMARY
If the repairDatabase command cannot create a directory during the repair process, it can abort the repair and delete the temporary files, which may in certain cases be the only copy of the data. This is a regression from 2.4 where the repair would leave the partially repaired data in a temporary directory.
USER IMPACT
Users affected by this issue can potentially lose the data they are trying to repair.
WORKAROUNDS
It is highly recommended to make a backup copy before running a repair. For replica set nodes, a node can be fully resynced from another member instead of repairing it. Ensuring correct file permissions for the mongodb user will also avoid the issue.
RESOLUTION
The removal of database files now happens after the directory creation, leaving the files in the temporary directory intact on failure. This restores the previous behavior of version 2.4.x.
AFFECTED VERSIONS
Version 2.6.0 is affected by this issue.
PATCHES
The patch is included in the 2.6.1 production release.
Original description
When performing a database repair, if a failure occurs while trying to move the temporary files, all of the data can be deleted.
2014-04-24T17:28:02.466-0500 [FileAllocator] done allocating datafile M:\db\_tmp_repairDatabase_0\Dev\Dev.7, size: 2047MB, took 0.001 secs 2014-04-24T17:28:21.866-0500 [conn86] removeJournalFiles 2014-04-24T17:28:25.840-0500 [conn86] Assertion: 13294:caught exception: boost::filesystem::create_directory: Access is denied: "M:\db\Dev" src\mongo\db\repair_database.cpp 443 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\util\stacktrace.cpp(169) mongo::printStackTrace+0x43 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\util\log.cpp(122) mongo::logContext+0x9c 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\util\assert_util.cpp(183) mongo::msgasserted+0xfb 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\util\assert_util.cpp(174) mongo::msgasserted+0x13 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\repair_database.cpp(443) `mongo::repairDatabase'::`1'::catch$2+0xa3 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe f:\dd\vctools\crt_bld\SELF_64_amd64\crt\prebuild\eh\amd64\handlers.asm(44) _CallSettingFrame+0x20 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe f:\dd\vctools\crt_bld\self_64_amd64\crt\prebuild\eh\frame.cpp(1337) __CxxCallCatchBlock+0xeb 2014-04-24T17:28:31.364-0500 [conn86] ntdll.dll RtlCaptureContext+0x3c3 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\repair_database.cpp(443) mongo::repairDatabase+0x1d6b 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\dbcommands.cpp(280) mongo::CmdRepairDatabase::run+0x25b 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\dbcommands.cpp(1357) mongo::_execCommand+0x5e 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\dbcommands.cpp(1575) mongo::Command::execCommand+0xf41 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\dbcommands.cpp(1650) mongo::_runCommands+0x4a7 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\query\new_find.cpp(107) mongo::runCommands+0x41 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\query\new_find.cpp(384) mongo::newRunQuery+0x49d 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\instance.cpp(269) mongo::receivedQuery+0x44f 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\instance.cpp(434) mongo::assembleResponse+0x30b 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\db\db.cpp(202) mongo::MyMessageHandler::process+0x111 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\mongo\util\net\message_server_port.cpp(210) mongo::PortMessageServer::handleIncomingMsg+0x677 2014-04-24T17:28:31.364-0500 [conn86] mongod.exe ...\src\third_party\boost\libs\thread\src\win32\thread.cpp(185) boost::`anonymous namespace'::thread_start_function+0x21 2014-04-24T17:28:31.364-0500 [conn86] 2014-04-24T17:28:31.368-0500 [conn86] cleaning up failed repair db: Dev path: M:\db\_tmp_repairDatabase_0