The server-status-journaling document reports on data that reflect this mongod instance’s journaling-related opera- tions and performance during a journal group commit interval (page 235). The server-status-journaling information only returns for instances that use the MMAPv1 storage engine and have journaling enabled: 

"dur" : { "commits" : <num>, "journaledMB" : <num>, "writeToDataFilesMB" : <num>, "compression" : <num>, "commitsInWriteLock" : <num>, "earlyCommits" : <num>, "timeMs" : { "dt" : <num>, "prepLogBuffer" : <num>, "writeToJournal" : <num>, "writeToDataFiles" : <num>, "remapPrivateView" : <num>, "commits" : <num>, "commitsInWriteLock" : <num> } }, 

The fields in the server-status-extra-info document provide platform specific information. The following example block is from a Linux-based system: 

"extra_info" : { "note" : "fields vary by platform", "heap_usage_bytes" : <num>, "page_faults" : <num> }, 

The server-status-globallock field reports on MongoDB’s global system lock. In most cases the locks document provides more fine grained data that reflects lock use: 

"globalLock" : { "totalTime" : <num>, "currentQueue" : { "total" : <num>, "readers" : <num>, "writers" : <num> }, "activeClients" : { "total" : <num>, "readers" : <num>, "writers" : <num> } }, 

The server-status-locks section reports statistics for each lock type and mode: 

"locks" : { "Global" : { "acquireCount" : { "r" : NumberLong(<num>), "w" : NumberLong(<num>), "R" : NumberLong(<num>), "W" : NumberLong(<num>) }, "acquireWaitCount" : { "r" : NumberLong(<num>), 

