Upgrade a Replica Set to 3.6
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MongoDB 3.6 is not tested on APFS, the new filesystem in macOS 10.13 and may encounter errors.
Starting in MongoDB 3.6.13, MongoDB 3.6-series removes support for Ubuntu 16.04 PPCLE.
For earlier MongODB Enterprise versions that support Ubuntu 16.04 POWER/PPC64LE:
Due to a lock elision bug present in older versions of the
glibcpackage on Ubuntu 16.04 for POWER, you must upgrade the
glibcpackage to at least
glibc 2.23-0ubuntu5before running MongoDB. Systems with older versions of the
glibcpackage will experience database server crashes and misbehavior due to random memory corruption, and are unsuitable for production deployments of MongoDB
Before you attempt any upgrade, please familiarize yourself with the content of this document.
If you need guidance on upgrading to 3.6, MongoDB offers major version upgrade services to help ensure a smooth transition without interruption to your MongoDB application.
When upgrading, consider the following:
To upgrade an existing MongoDB deployment to 3.6, you must be running a 3.4-series release.
To upgrade from a version earlier than the 3.4-series, you must successively upgrade major releases until you have upgraded to 3.4-series. For example, if you are running a 3.2-series, you must upgrade first to 3.4 before you can upgrade to 3.6.
Before beginning your upgrade, see the Compatibility Changes in MongoDB 3.6 document to ensure that your applications and deployments are compatible with MongoDB 3.6. Resolve the incompatibilities in your deployment before starting the upgrade.
Before upgrading MongoDB, always test your application in a staging environment before deploying the upgrade to your production environment.
Once upgraded to 3.6, if you need to downgrade, we recommend downgrading to the latest patch release of 3.4.
Starting in MongoDB 3.6,
mongos instances bind to localhost by default. Remote clients, including other members of the replica set, cannot connect to an instance bound only to localhost. To override and bind to other ip addresses, use the
net.bindIp configuration file setting or the
--bind_ip command-line option to specify a list of ip addresses.
The upgrade process will require that you specify the
net.bindIp setting (or
--bind_ip) if your replica set members are run on different hosts or if you wish remote clients to connect to your replica set.
Before binding to a non-localhost (e.g. publicly accessible) IP address, ensure you have secured your cluster from unauthorized access. For a complete list of security recommendations, see Security Checklist. At minimum, consider enabling authentication and hardening network infrastructure.
For more information, see Localhost Binding Compatibility Changes
Before starting the upgrade, ensure that no initial sync is in progress. Performing the upgrade while an initial sync is in progress will cause the initial sync to restart.
Starting in MongoDB 3.6, MongoDB enables support for
"majority" read concern by default.
For MongoDB 3.6.1 - 3.6.x, you can disable read concern
"majority" to prevent the storage cache pressure from immobilizing a deployment with a primary-secondary-arbiter (PSA) architecture. Disabling
"majority" read concern also disables support for Change Streams
For more information, see Disable Read Concern Majority.
- Version 3.4
All replica set members must be running version 3.4. To upgrade a replica set from an 3.2-series and earlier, first upgrade all members of the replica set to the latest 3.4-series release, and then follow the procedure to upgrade from MongoDB 3.4 to 3.6.
- Feature Compatibility Version
The 3.4 replica set must have
To ensure that all members of the replica set have
3.4, connect to each replica set member and check the
All members should return a result that includes
To set or update
featureCompatibilityVersion, run the following command on the primary. A majority of the data-bearing members must be available:
For more information, see
If you installed MongoDB from the MongoDB
zypper repositories, you should upgrade to 3.6 using your package manager.
Follow the appropriate 3.6 installation instructions for your Linux system. This will involve adding a repository for the new release, then performing the actual upgrade process.
You can upgrade from MongoDB 3.4 to 3.6 using a “rolling” upgrade to minimize downtime by upgrading the members individually while the other members are available:
Upgrade the secondary members of the replica set one at a time:
Shut down the
mongodinstance and replace the 3.4 binary with the 3.6 binary.
Restart the member.
rs.status() shows that the primary has stepped down and another member has assumed
PRIMARY state, upgrade the stepped-down primary:
At this point, you can run the 3.6 binaries without the 3.6 features that are incompatible with 3.4.
To enable these 3.6 features, set the feature compatibility version (
FCV) to 3.6.
Enabling these backwards-incompatible features can complicate the downgrade process since you must remove any persisted backwards-incompatible features before you downgrade.
It is recommended that after upgrading, you allow your deployment to run without enabling these features for a burn-in period to ensure the likelihood of downgrade is minimal. When you are confident that the likelihood of downgrade is minimal, enable these features.
Ensure that no initial sync is in progress. Running
setFeatureCompatibilityVersion command while an initial sync is in progress will cause the initial sync to restart.
On the primary, run the
setFeatureCompatibilityVersion command in the
This command must perform writes to an internal system collection. If for any reason the command does not complete successfully, you can safely retry the command on the primary as the operation is idempotent.