This is an old version. A new version that only requires a single BaSH script is available here:

https://github.com/Zerto-TA-Public/Zerto-MongoDB-Checkpoints-Linux

MongoDB-Journal-Checkpoints

These scripts are used to add a Quiesced User Checkpoint to the Zerto Journal of a MongoDB server. The result is that MongoDB will flush all pending writes to disk, and pause new writes long enough for Zerto to insert a checkpoint into the journal which has all database records.

Getting Started

There are several pieces to this project. Some of which are placed on your Linux based MongoDB server, and another that gets placed on a Windows based machine.

At a high level the process for a MongoDB Journal Checkpoint looks like this:

1. Windows Scheduled Task (or other scheduling engine) calls the MongoDB-Journal-Checkpoint.ps1 script
2. The Powershell script connects to the MongoDB Linux Server
3. The MongoDB server executes mongo_freeze.sh script, which freezes MongoDB
4. The Powershell script verifies that the DB is locked (if not it tries two more times).
5. The PowerShell script calls ZVM and inserts a User Checkpoint for the specified VPG
6. The PowerShell script executes mongo_unfreeze.sh script, which unfreezes MongoDB (it will continue to retry until the DB is unlocked).
7. The PowerShell script disconnects the SSH session

Prerequisites

• Zerto PowerShell Module must be installed on the Windows Machine
• PoSH-SSH PowerShell Module must be installed on the Windows Machine
• You must create an RSA keypair for passwordless authentication to your MongoDB Linux Server (and copy the private key to the Windows Machine)
• PowerShell "Set-ExecutionPolicy Unrestricted" on Windows Machine

Set-ExecutionPolicy Unrestricted

Installing

Download or clone the git repository to your Linux MongoDB server, then make the two bash scripts (mongo_freeze.sh and mongo_unfreeze.sh) executable. After that copy them to /usr/local/bin or another directory in your user accounts PATH.

git clone https://www.github.com/zerto-ta-public/MongoDB-Journal-Checkpoint/
chmod +x mongo_*
sudo cp mongo_* /usr/local/bin/

Next, to enable password-less authenication, create an RSA keypair on the MongoDB server and add the public key to the authorized_keys file.

When asked the questions by ssh-keygen, just hit enter on all questions.

ssh-keygen rsa
cat ~/.ssh/id_rsa >> ~/.ssh/authorized_keys

Next move both the private key from your .ssh/ folder as well as the Zerto-Mongo-Checkpoint.ps1 script to your Windows host using WinSCP or something similar.

Usage

For a full walkthrough of this project please see https://www.jpaul.me/?p=12645

Versioning

This script is considered the initial release and version 1.0.0

Authors

• Justin Paul - Initial work - recklessop - Blog

Contributors

• Shannon Snowden - Script Review - shannonsnowden - Blog

License

This project is licensed under the GNU GPLv3 License - see the LICENSE.md file for details

Acknowledgments

• Google
• Zerto Documentation
• etc