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- db.fsyncUnlock()
db.fsyncUnlock()¶
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Definition¶
-
db.
fsyncUnlock
()¶ Unlocks a
mongod
instance to allow writes and reverses the operation of adb.fsyncLock()
operation. Typically you will usedb.fsyncUnlock()
following a database backup operation.db.fsyncUnlock()
is an administrative operation.
Compatibility with WiredTiger¶
Changed in version MongoDB: 3.2
db.fsyncLock()
ensures that the data files are safe to copy
using low-level backup utilities such as cp
, scp
, or
tar
. A mongod
started using the copied
files contains user-written data that is indistinguishable from the
user-written data on the locked mongod
.
Prior to MongoDB 3.2, db.fsyncLock()
cannot guarantee that
WiredTiger data files are safe to copy using low-level backup
utilities.
The data files of a locked mongod
may change due to
operations such as journaling syncs or
WiredTiger snapshots. While
this has no affect on the logical data (e.g. data accessed by
clients), some backup utilities may detect these changes and emit
warnings or fail with errors. For more information on MongoDB-
recommended backup utilities and procedures, see
MongoDB Backup Methods.