Support for WiredTiger Storage Engine in CPS for MongoDB Upgrade
Feature Summary and Revision History
Applicable Product(s) or Functional Area |
CPS |
Applicable Platform(s) |
Not Applicable |
Default Setting |
Enabled – Configuration Required |
Related Changes in This Release |
Not Applicable |
Related Documentation |
|
Revision Details |
Release |
---|---|
First introduced |
22.1.1 |
Feature Description
In CPS 22.1.1 and later releases, if you want to upgrade CPS from prior releases, change the storage engine from MMapV1 to WiredTiger. The prerequisites for upgrading to 22.1.x release are:
-
Set the 4.0 replica set to CompatibilityVersion 4.0. To ensure that all members of the replica set have featureCompatibilityVersion set to 4.0, connect to each replica set member and check the featureCompatibilityVersion:
db.adminCommand( { getParameter: 1, featureCompatibilityVersion: 1 } )
All members return a result that includes "featureCompatibilityVersion" : { "version" : "3.6" }.
-
To set or update featureCompatibilityVersion, run the following command on the primary. Most of the data-bearing members must be available:
db.adminCommand( { setFeatureCompatibilityVersion: "4.0" } )
Note |
In CPS 22.1.1, PCRF runs with Mongo DB 4.0.27 and Mongo Java Driver 3.12.9. The compatible driver for both Mongo 4.0 and 4.2 is 3.11 and above. |
For more information, see the Configuration Parameters - HA System table in the CPS Installation Guide for OpenStack and Modification of Storage Engine before Upgrade.
Memory and Performance Impact
Wired Tiger Storage engine change in MongoDB Server 4.0 requires additional CPU resources of ~15% and additional memory (RAM) resources of ~40% in the Session Manager VMs. Up to ~40% more memory being consumed more by wiredtiger from total memory(RAM) than MMapV1.
For example, if the session manager VM(150GB) with MMapV1 utilizes 60GB then, wiredtiger requires 120GB(MMapV1 usage 60GB + 40% of total memory 150GB).
Upgrade, Migrate, and Backward Compatibility Considerations
You can upgrade CPS 21.1.0 or 21.2.0 to CPS 22.1.1, and then to CPS 22.2.0 with ISSM process. Upgrade from prior to CPS 21.1.0 releases is not supported.
During the ISSM process, a new VM is created, and then a replica set member is newly created with only a new mongo version.
Prerequisites for the ISSM Process
The following are the Prerequisites:
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Take a copy of the mongoConfig.cfg file in both old Cluster Managers.
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Update the following values in mongoConfig.cfg file:
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WT_CACHESIZEGB=12
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WT_CACHEARBSIZEGB=1
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Execute import_deploy.sh before performing ISSM procedure.
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Make sure that the system is running mongo 3.6 and Java driver patch is applied on the system.
After the prerequisites conditions are met, perform the ISSM process.
Roll back Procedure
Before performing a rollback, restore the copied mongoConfig.cfg file in older Cluster Managers.
Execute the import_deploy.sh before performing ISSM rollback procedure.