The term “snapshot” can be confusing. When people discuss it in the context of backup and file systems, they’re not always talking about the same thing. So we’re going to clearly define snapshots with regards to the Nasuni Filer—what the term means and what tools you can use to take advantage of snapshots.
Instant, Complete Pictures of Your Data
With the Filer, a snapshot is a complete picture of your data at a specific moment in time. It is instantaneous. Once a snapshot has been taken, and is pushed to the cloud, it is not possible to modify that snapshot.
Built-In Backup
Snapshots are the reason you don’t need backups for the data stored on your Nasuni Filer. Our technology delivers built-in, secure backups via snapshots, and allows you to roll back to any point in the lifetime of a file or directory. Apple does something similar with Time Machine, the free utility it ships with Mac OSX.
The Snapshot Process
The Nasuni Filer starts a snapshot by working off a frozen copy of the data in the local cache at a given instant—it is a true snapshot, not a Time-Machine-like rolling copy. The Filer checks this frozen copy for changes such as modified files and directories. These changes are then scheduled to be pushed to the cloud. Changes that occur while the snapshot is taking place will be captured in the next snapshot.
As for the modifications, only the changed pieces of a given file are pushed, not the entire file. This reduces the amount of data stored in the cloud and helps you save on costs.
The Filer encrypts, compresses, and applies a modification detection code to each chunk of data—which might be an entirely new file or just an altered piece of an existing one—before pushing it to the cloud. This ensures the security and integrity of files (in the case of read-back) and further reduces storage fees (thanks to compression).
Optimization
Once the changes have been identified, the Nasuni Filer begins sending the data to the cloud as quickly as it can (or is allowed to per the Quality of Service settings in the UI). If the connection to a cloud vendor is interrupted during the process of creating and pushing a snapshot, we pick up where we left off, ensuring that for that moment in time, you will still have a good snapshot.
Tools and Controls
As the Administrator of the Nasuni Filer, you have a few options in terms of managing and interacting with snapshots. The Quality of Service configuration allows you to set the amount of bandwidth that a given snapshot operation can consume at a given day or time:
The Filer also lets you set the frequency of your snapshots. If you, as the Administrator, know that your data changes often, and you want frequent, small snapshots, you can adjust accordingly in the Administration UI:
These two tools give you granular control over exactly when and how quickly snapshots are created for the Filer. You can optimize the process for your local environment, the size of your cache, or the speed of your internet connection.
Administration UI
Thanks to the Administration UI, you can view your entire snapshot history, right back to the beginning of the life of your Nasuni Filer:
Through this same page, you can restore files and directories—overwrite existing ones, rename, etc.. Restores are instant due to the design of the snapshot system itself:
This UI also gives you the ability to peek into a snapshot to ensure that the data you are about to restore really is the data you wish to restore. This saves you, as the Administrator, precious time and effort.
Snapshot Integrity
We include tools that execute periodically to ensure the integrity of a given snapshot. These tools analyze the stored data, but are not part of the normal path—they operate as a background process, slowly checking and rechecking for problems. If missing data or cloud data corruption is detected, the system raises an alert. You stayed informed when things go wrong. Nasuni will know immediately, too, and begin working to fix it.
We’ve dedicated quite a few posts already to the features of the Nasuni Filer. But we feel that this snapshot technology— self-managed and flexible, with secure, reliable backups built into the core —is really one of the key components that set it apart.