In the world of virtualization, VMware vSphere proves to be an outstanding platform that provides features for managing virtual machines (VMs). The crucial factor of VM management is to ensure data protection through backup.
In this blog, we will explore the concept of quiescing in VMware vSphere VMs and its significance for backup.
What is a Snapshot?
A snapshot of a virtual machine is a copy of the virtual machine’s state at a specific point in time. This includes the virtual machine’s power state (powered-on, powered-off, or suspended) and all the files of the virtual machine. You can take a snapshot of a virtual machine when it is powered on, powered off, or suspended. Snapshots are useful when you want to revert repeatedly to a virtual machine state, but you do not want to create multiple virtual machines.
How Snapshot Works?
When you create a snapshot, VMware vSphere captures the virtual machine’s OS, disk data, and configuration settings. This enables you to restore the VM to the exact state it was in when the snapshot was taken. Snapshots essentially provide a way to preserve the state of a VM, enabling you to revert to a previous state if needed. For example, You can create a snapshot before updating the OS, if you face any issues, you can easily revert to the previous state of the machine.
Check out the article Understanding VMware Snapshot to learn about working and best practices.
Is VM Snapshot a backup?
While snapshots can be a useful tool for backing up virtual machines, they are not a complete backup solution. Snapshots are dependent on the VM’s storage. If the storage is not available due to any case, then you will not be able to restore your VMs with snapshots. Also, Snapshots do not provide the same level of protection as regular backups because they only capture a point-in-time image of the VM, and do not necessarily include all data needed for a complete restore. It’s very important to prioritize VM backup over VM Snapshot because backups are necessary to keep your business running.
Check out the article VM Snapshot vs Backup to learn more.
Types of Snapshots in VMware
- Memory State Snapshots
- Quiesced Snapshots
Memory State Snapshots
VMware vSphere offers the option to take memory state snapshots to retain the active state of a VM. When you capture a memory state snapshot, the VM is stunned to serialize its state to disk and close any running disks. This process ensures that the captured state is consistent and can be accurately restored.
However, it is important to note that memory snapshots are not a backup. They are best suited for saving the state of running applications during upgrades or other temporary changes.
Quiesced Snapshots
Along with memory state snapshots, VMware vSphere allows you to capture quiesced snapshots. Quiescing refers to the process of bringing a VM’s data and file system into a consistent state suitable for backups. This is important when you want to ensure the integrity and consistency of your VMs during backup operations.
When you capture a quiesced snapshot, VMware Tools works in conjunction with the guest operating system to prepare the VM for snapshot creation. The process involves leveraging a new Volume Snapshot Service (VSS) snapshot inside the guest OS , which ensures that ongoing processes and data are properly handled before the snapshot is taken. This way, the resulting snapshot represents a consistent view of the guest file system at a specific point in time.
Benefits of Quiesced Snapshots
Quiesced snapshots has advantages when it comes to performing backups in VMware vSphere environments.
1. Data Consistent Backup
Quiesced snapshots help bring the file system and application data in a VM to a consistent state before taking a snapshot. By temporarily suspending or altering ongoing processes, quiescing ensures that all pending data and file system changes are written to disk. This ensures data integrity while taking a backup.
2. Application Aware Backup
Quiesced snapshots improve the ability to capture active applications data during backups. By ensuring that active applications complete their tasks and flush their buffers to disk, quiescing provides an application-consistent snapshot. This is particularly useful for applications like Oracle and SQL, where consistent backups.
How to Create a Quiesced Snapshot
Follow these steps to create a quiesced snapshot in vSphere:
- Open your web browser and navigate to the vSphere Web Client
- Locate and select the virtual machine for which you want to create a quiesced snapshot
- In the vSphere Web Client, go to the “Monitor” tab and select “Virtual Machines.”
- Right-click on the virtual machine and choose “Snapshot” > “Take Snapshot.”
- On the Take Snapshot dialog box, Enter a name and description for the snapshot
- Check the option for “Quiesce guest file system” (Needs VMware Tools installed)
- Deselect Include virtual machine’s memory option
- Finally, click the ‘Create‘ button to create the quiesced snapshot
Benefits of VM Quiescing for VMware Backup
- Data Consistency: Ensures that data within the virtual machine is in a consistent state at the time of backup
- Application-Awareness: Safeguards application data by pausing or synchronizing applications during the backup process. Especially beneficial for application-aware backups, ensuring coordination with applications for data consistency
- Transaction Completeness: Facilitates the completion or rollback of transactions within applications before backup, preventing data inconsistencies
- Snapshot Stability: Enhances the reliability of snapshots by freezing the VM in a stable state, reducing potential snapshot-related issues
- File System Coherence: Temporarily halts write operations to achieve file system coherence, avoiding mixed data capture during backup
- Reliable Recovery: Contributes to more reliable and coherent recovery processes, reducing the risk of data corruption
VMware Backup Solutions with Quiescing Capabilities
VMware backup tools incorporate VMware quiescing as a key feature to ensure the reliability and consistency of virtual machine backups.
BDRSuite is one of the comprehensive and cost-effective VMware backup solutions that utilizes VMware quiescing to achieve the following benefits:
- Application-consistent Backup
- Transaction Handling
- Snapshot Stability
- Efficient Backup Operations
- Enhanced Application Awareness
- Reliable VM Restore
Check out the article to learn step by step instructions on how to configure VMware Quiesced Snapshot Backup using BDRSuite.
Best Practices for VMware Backup with Quiesced Snapshots using BDRSuite
Enable VMware Quiescing
Enable VMware quiescing within the backup job settings to leverage VMware Tools for application and file system consistency. Ensure that VMware Tools is installed and up-to-date on each virtual machine.
Application-Aware Backup Solutions
BDRSuite’s application-consistent backups is specifically designed to understand the intricacies of different applications and ensure that backups capture a consistent state. Application-aware backup solutions can greatly enhance the reliability and recoverability of your VMs, particularly for critical applications.
Automation and Regular Backups
By creating quiesced snapshots, BDRSuite can easily capture snapshots of your VMs at regular time intervals. This ensures that you have backups available for recovery purposes, without the need for manual intervention.
Regular Testing and Verification
Backup & Recovery process should be periodically tested to ensure their recoverability. BDRSuite perform test mount and boot check to validate the integrity of your backups and ensure that you can successfully recover your VMs when needed.
Conclusion
Quiesced snapshots in VMware vSphere provide an essential capability for achieving consistent and reliable backups of your VMs. By leveraging quiescing, you can ensure data integrity, support active applications, and automate regular backup processes.
However, it’s important to remember that quiesced snapshots should be part of a comprehensive VMware backup strategy. By following best practices, you can confidently protect your VMware vSphere VMs and safeguard your critical data.
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