As businesses embrace the cloud, data continuity and data protection stand as a cornerstone for resilient business operations. IBM Cloud® offers Block Storage for VPC as a foundational building block, providing not only high-performance block storage but also a robust backup and recovery mechanism for safeguarding your data.
IBM Cloud Block Storage Snapshots for VPC is a powerful tool for creating point-in-time backups of individual volumes. Leveraging a differential approach, Block Storage Snapshots for VPC capture only the changes made since the last snapshot, minimizing storage usage and optimizing backup processes. This granularity aims not only data integrity but also efficiency in storage management.
On this blog, we will explore and unravel the finer details of IBM Cloud Block Storage Multi-Volume Snapshots for VPC, recognizing their significance and guiding you through the steps to seamlessly capture and manage consistent backups across multiple volumes.
Challenges with single-volume snapshot
While Block Storage Snapshots for VPC excel in providing consistent backups for individual volumes, complexities arise when dealing with multi-volume environments. Synchronizing snapshots across multiple volumes introduces the challenge of maintaining consistency across the entire dataset. Addressing these challenges is crucial to establishing a comprehensive backup strategy.
Snapshot consistency groups
To overcome the challenges of capturing multi-volume snapshots, IBM Cloud is introducing the concept of snapshot consistency groups. Snapshot consistency groups aim for data across multiple volumes to be in a consistent state as if the system had crashed at a specific point in time. A snapshot consistency group contains snapshots of multiple block storage (boot and data) volumes that are attached to the same virtual server instance (VSI; instance storage is not included).
When you take a snapshot of a consistency group, the system aims that all write operations are complete before it takes the snapshots. Then, the system captures the snapshots of all the opted-in block storage volumes that are attached to the VPC VSI at the same time.
The snapshot consistency group has its own lifecycle, and it keeps references to the member snapshots. So if a member snapshot is deleted or renamed, the consistency group is also updated. The snapshots in the group are loosely coupled, and you can manage the snapshots within a consistency group the same way you manage any other snapshot. You can delete individual snapshots from the consistency group if you want to, or you can keep individual snapshots after you decide to delete the consistency group, but you can’t add a new snapshot member to an existing snapshot consistency group.
You can use the members of the snapshot consistency group to restore volumes separately, and you can also create cross-regional copies of the members of the snapshot set separately, but you can’t create a copy of a consistency group in another zone or region.
How to create a multi-volume snapshot
Creating a multi-volume snapshot is as easy as creating a single-volume snapshot, you can create and manage your multi-volume snapshots, which is snapshot consistency groups from UI, CLI, API or with Terraform¹. The following steps will show you how to create a multi-volume snapshot of the volumes attached to a running VSI within the IBM Cloud console:
1. Within the VPC Infrastructure section in the IBM Cloud console, access the Block storage snapshots subsection and click on Create. Alternatively, you can search for Block storage snapshots and that will bring up the snapshot provisioning page:
2. Select the Multiple volumes card, then select the VSI that has the attached volumes you want to snapshot:
3. Enter the name for this new consistency group and any optional tags you might want to add:
4. Finally, review the volumes that are part of your consistency group and click on Create block storage snapshot consistency group:
You will now be able to find your snapshot consistency group and all the members on the Block storage snapshots subsection within the VPC Infrastructure section:
Restoring to a new VSI from a snapshot consistency group is also easy:
1. Click on the consistency group name to enter the details page and then click on Create virtual server:
2. Your boot and data snapshots are preselected, enter the new VSI details and click on Create virtual server:
Your new VSI was created using the snapshot consistency group. All the members of your consistency group were restored to new volumes attached to your new VSI:
Things to keep in mind when using multi-volume snapshots
- Availability: This feature is available in all MZRs.
- Backup-policy integration: The snapshot-taking process can be automated by using IBM Cloud Backup for VPC.
- Performance: Creating crash-consistent snapshots of multiple VSI volumes leads to a short-lived I/O suspension that can last from a few milliseconds to a few seconds. The duration depends on the size and quantity of volumes connected to your VSI. It is recommended to run your automated backup-policy during off-peak hours to minimize any impact on performance.
- Billing: There is no additional cost to use the multi-volume snapshot feature. However, normal snapshot billing applies for snapshot space used.
Getting started with IBM Cloud Block Storage for VPC
If you are not already an IBM Cloud customer, it’s easy to sign up and get started. If you are already a customer, you can now provision VPC block volumes using the IBM Cloud Console, API or CLI.
Get up to USD 1,000 in credits for new VPC block volumes and VPC infrastructure by using the code VPC1000 at the time of provisioning or through the billing and usage section in IBM Cloud Console.