Better NAS Backup RPO with Changelist Snapshots
Although NDMP has long been the de facto approach for protecting NAS data, some limitations have led Rubrik to choose a different approach from day 1, leveraging NFS and SMB instead. To ensure that customers are able to reliably protect their data and recover quickly from data corruption and data loss, Rubrik takes an approach that obviates the need for complex NDMP implementations.
NAS protection with Rubrik utilizes a three-phase approach. Each phase is optimized using modern techniques such as snapshot API integration, data partitioning, and parallel file streaming.
The Rubrik three-phase approach for NAS protection includes:
- Scan: Rubrik identifies which files need to be protected for full or incremental backups.
- Fetch: Rubrik takes the list of files from the Scan phase and reads them over the NAS protocol.
- Copy: Rubrik compresses, encrypts, and writes the data to either the Rubrik cluster or, using NAS Direct Archive, to an archive location on-premises or in the cloud.
NAS Data Scan
File scanning has historically been the biggest bottleneck for NAS backup performance. This challenge has only grown as the amount of data has grown. Previous approaches, such as image-level backups, have increased backup performance by avoiding file scanning altogether. But that approach has made file-level recovery complex and slow while often locking customers into proprietary backup formats. Modern approaches such as snapshot and file change API integrations have provided much needed improvements for NAS platforms integrated with data management platforms via APIs.
When snapshot API integration is not available, Rubrik will mount the NAS share to be protected vis NFS or SMB and read the metadata of each file enumerated in a fileset. The first backup of a file system will always be a full backup, which means Rubrik will scan and index every file in the fileset. For an incremental backup, Rubrik performs the following operations:
- Scans the metadata of each file.
- Compares the attributes of a file, such as the last modified time, against the last backup to identify the changes.
- Marks a file to be protected if the file has been modified since the last backup.
Changing the Game with Snapshot Changelist
Introduced in Rubrik CDM version 5.1.1, the integration with snapshot changelist cuts NAS data scan times down.
SnapDiff is an internal NetApp Data ONTAP engine that quickly identifies the file and directory differences between two snapshot copies. By doing this, we eliminate the need for Rubrik to do a traditional scan for changed files. Instead, an API call will return to Rubrik a list of files that have been added, modified, or deleted since the last backup from a NetApp NAS. This reduces the backup window to only the time it takes to fetch and write the changed or added data.
The backup workflow with the Changelist Snapshot using the SnapDiff API is as follows:
- Rubrik invokes the NetApp ONTAP snapshot API to create the first backup. Note that ONTAP snapshot API integration is required with Changelist Snapshot API integration and is supported by Rubrik CDM. The first backup will be a full copy of the active file system.
- Rubrik mounts and protects the full snapshot using our optimized scan method.
- On the next run, Rubrik invokes the ONTAP snapshot API again to create a new snapshot.
- Rubrik invokes the Changelist Snapshot API to compare the current snapshot against the previous snapshot.
- Rubrik receives, via the Changelist Snapshot API, a list of changes since the previous snapshot was taken. This step obviates the need for Rubrik to conduct a scan of the file system.
- Rubrik performs an incremental backup that only includes the changed files.
- Rubrik invokes the ONTAP snapshot API to delete the older of the 2 remaining snapshots.
Archiving to Public Cloud with Changelist Snapshots
Rubrik is the first vendor on the market that can backup NetApp NAS with Changelist Snapshots and archive the data to public cloud storage! And combined with Rubrik’s NAS Direct Archive, customers no longer have to worry about backup of very large NetApp NAS data sets that used to take too long and consume too much storage on-premises.
In order to take advantage of the proprietary APIs as a partner of NetApp, there are some important considerations to bear in mind. As part of this agreement, the following applies when using Changelist Snapshots with Rubrik CDM:
- When archival is enabled on an SLA Domain, the archival location must be either a NetApp storage target, such as NetApp StorageGRID, or public cloud storage.
- Data that was backed up using Changelist Snapshots can only be restored to a NetApp NAS.
Introducing support of Changelist Snapshots in Rubrik CDM now allows our joint customers to shorten the backup window of their large NetApp NAS. Backup frequency of more critical file sets can be increased, enabling shorter RPO, while at the same time reducing secondary storage footprint on-premises.
For a deeper dive into Rubrik NAS backup, read our white paper.