File System Replication
Cross-region replication for File Storage provides protection from regional outages, aids in disaster recovery efforts, and addresses data redundancy compliance requirements.
Learn how to replicate the data in one file system to another file system in the same region or a different region.
- SOURCE FILE SYSTEM
The file system whose data you want to replicate to another region or availability domain at regular intervals. Visit the source file system Details page for replication information.
- TARGET FILE SYSTEM
The destination for replicated data from the source file system. Only a file system that has never been exported can be used as a target file system. Visit the target file system Details page for replication information.
- REPLICATION RESOURCE
This is the control component of the replication process. It contains all of the necessary configuration information for the replication. The replication resource is attached to the source file system. It captures data updates by creating a replication snapshot and then transmits the snapshot to the replication target. Replications are listed in the Resources section of the source file system's Details page. Visit the replication's Details page for information about the replication.
- REPLICATION TARGET RESOURCE
- The replication target resource resides in the destination region and availability domain. It receives a replication snapshot from the replication resource and applies the data to the target file system. The replication target is automatically created when you create a replication resource. The only operation that you can perform manually on a replication target resource is to delete it during a failover procedure. You can see a file system's Replication Target link in its Details page. Visit the replication target's Details page for information about the replication target.
- REPLICATION SNAPSHOT
- Captures incremental changes in the source file system since the last snapshot. The snapshot data is transmitted from the replication resource to the replication target, which applies it to the target file system. Replication snapshots are managed by the service. Replication snapshots are listed in the source and target file system's Snapshots page. See Replication and Snapshots for more information.
- DELTA CYCLE
A complete replication operation.
- Idle: The replication is not capturing or applying data.
- Capturing: The replication is capturing differentiated data in the source snapshot.
- Transferring: The replication is both capturing and committing snapshot data.
- Applying: The replication is committing the snapshot data to the target file system.
- REPLICATION INTERVAL
- The frequency that the replication operation is performed. You specify the interval when you create the replication resource.
- RECOVERY TIME OBJECTIVE (RTO)
- The maximum length of time allowed between an unexpected failure or disaster and the resumption of normal operations. The RTO defines the point in time after a disaster when the consequences of interruption become intolerable.
- RECOVERY POINT OBJECTIVE (RPO)
- The maximum acceptable amount of data loss measured in time. In the event that the source file system fails, the RPO is the last replication snapshot that was transmitted to the target. Visit the replication target's Details page for information about the replication target.
How Replication Works
To enable File Storage replication, you create a replication resource attached to the source file system. The replication resource specifies the target file system to replicate to, and how often the data is replicated. The location of the target file system can be in the same or different availability domain as the source file system, in the same or different region. Only a file system that has never been exported can be used as a target file system. After the replication resource is created, the target file system is read-only and updated only by replication. Data updates to the source file system are asynchronously replicated to the target file system. See Creating a Replication.
Replicated data in the target file system has the same file and folder structure, snapshots, metadata, and permissions settings as the source file system. File system-specific data such as file locks, encryption keys, and tags are not replicated. Clones of the source file system are not replicated. Keys and tags for the target file system must be configured separately.
The Replication Process
The replication resource creates a special replication snapshot in the source file system. Then, it transfers the snapshot to the replication target resource, which writes the new data to the target file system. The last completed replication snapshot remains in both the source and target file system until the next interval. At the next interval, the replication process automatically deletes the old replication snapshots and creates a new one. The replication process continues to repeat at the specified interval as long as the replication is in effect.
If there's an outage in the primary (source) availability domain, you can fail over to the target file system. To fail over to the target file system, export it so applications and users can access it. See Disaster Recovery for more information.
Monitoring Replications and Outages
The File Storage service provides metrics so that you can track replication operations and potential outages. You can use metrics to analyze things like transfer between the source and target file systems, bandwidth, and metadata operations performed by the replication resource. For example, to monitor bandwidth issues and potential bottlenecks, you can monitor the total number of write operations on the source file system and the total data egress from the source file system to target file system. You can also use metrics to monitor the time between snapshot creation on the source file system and the time it's applied to the target. In this way you can determine how far the target file system is behind the source, and how much data would be lost if there's an outage. See File System Metrics and Overview of Monitoring.
Oracle recommends that you configure alarms on metrics like the error rate and latency in the source file system to indicate any impact to availability. You can also monitor OCI announcements and status dashboard for general service outages so that you can make necessary decisions about failover. Service outages don't always impact all customer resources equally, so it is very important that you determine your tolerances and put alarms in place. See Console Announcements and Events.
You can perform the following replication tasks:
- Create a Replication
- Estimating Replication Time
- Listing Replications
- Listing Replication Targets
- Getting a Replication's Details
- Getting a Replication Target's Details
- Editing a Replication
- Deleting a Replication
- Deleting a Replication Target
- Using Replication for Disaster Recovery
- Using Replication for Data Transfer
Limitations and Considerations
- Your tenancy must be subscribed to the destination region for cross-region replication. To subscribe to a region, see Managing Regions. See Allowed Target Regions for more information.
- When you enable cross-region replication for a file system, the process includes an initial sync of the data from the source file system to the target file system. Depending on the amount of data written to the file system, this sync can take hours. See Estimating Replication Time for more information.
- You can configure up to three replication jobs for each file system.
- You can't use replication to migrate data from an on-premises location to Oracle Cloud Infrastructure.
- Only a file system that has never been exported can be used as a target file system. If you want to use a previously exported file system as a target, first create a clone of the file system. Then, you can use the clone as a target.
- If you create or delete user snapshots on a file system, you can't use that file system as a target file system for replications, even if you haven't exported the file system.
- A file system with a snapshot policy attached cannot be used as a target file system.
- If you delete a replication resource, replication snapshots on the target file system are converted to user snapshots. If you delete one of these snapshots, you can't re-use the target file system as a target file system for future replications.
Cost Considerations for Replication
After you enable replication for a file system, the file system is replicated to a target file system in the specified region and availability domain. File Storage is metered for your total capacity stored on disk for both the source and target file systems. Source and target file systems are priced at the same rate. See File System Usage and Metering for more information.
Your bill includes any applicable network costs for the replication process between regions. As part of the replication process, all data being updated on the source file system is transferred to the file system replica, so file systems with continual updates incur higher network costs. There is no additional charge for cross-availability domain bandwidth within the same region or inbound data transfer.
Many replication scenarios use a clone of an original source or target file system. Cloning the source from the last completely applied snapshot ensures that the source and target are compatible. You can also choose to use a new file system for failback. However, using a clone of the original source file system tends to be both faster and more cost effective than using a new file system. See Clone Metered Utilization for more information about metering and billing for clones. See Replication Metered Utilization for detailed examples of metering for file systems, snapshots, and clones as they’re used in replication.
Allowed Target Regions
When you enable replication for a file system, you select a destination region to replicate to. The source region for the file system determines the target regions available to select as a destination region for replication. Most regions have one or more regions available as possible destination regions. These target regions are selected based on geographical locations to maximize performance. To subscribe to a region, see Managing Regions.
The following table lists the region mappings for the Oracle Cloud Infrastructure commercial realm. Regions in Government Cloud realms allow replication to all other regions within the same realm.
|Source Region||Target Region|
|Australia East (Sydney)||Australia Southeast (Melbourne)|
|Australia Southeast (Melbourne)||Australia East (Sydney)|
|Brazil East (Sao Paulo)||
Brazil Southeast (Vinhedo)
|Brazil Southeast (Vinhedo)||Brazil East (Sao Paulo)|
|Canada Southeast (Montreal)||Canada Southeast (Toronto)|
|Canada Southeast (Toronto)||Canada Southeast (Montreal)|
|Chile (Santiago)||Brazil East (Sao Paulo)|
|France Central (Paris)||
France South (Marseille)
Italy Northwest (Milan)
|France South (Marseille)||
France Central (Paris)
Italy Northwest (Milan)
Spain Central (Madrid)
|Germany Central (Frankfurt)||
Netherlands Northwest (Amsterdam)
Sweden Central (Stockholm)
Switzerland North (Zurich)
UK South (London)
|India South (Hyderabad)||India West (Mumbai)|
|India West (Mumbai)||India South (Hyderabad)|
|Israel Central (Jerusalem)||UK South (London)|
|Italy Northwest (Milan)||
France South (Marseille)
France Central (Paris)
|Japan Central (Osaka)||Japan East (Tokyo)|
|Japan East (Tokyo)||
Japan Central (Osaka)
|Mexico Central (Queretaro)||US West (Phoenix)|
|Netherlands Northwest (Amsterdam)||Germany Central (Frankfurt)|
|Saudi Arabia West (Jeddah)||UAE East (Dubai)|
|Singapore (Singapore)||Japan East (Tokyo)|
|South Africa Central (Johannesburg)||UK South (London)|
|South Korea Central (Seoul)||South Korea North (Chuncheon)|
|South Korea North (Chuncheon)||South Korea Central (Seoul)|
|Spain Central (Madrid)||France South (Marseille)|
|Sweden Central (Stockholm)||Germany Central (Frankfurt)|
|Switzerland North (Zurich)||Germany Central (Frankfurt)|
|UAE Central (Abu Dhabi)||UAE East (Dubai)|
|UAE East (Dubai)||
Saudi Arabia West (Jeddah)
UAE Central (Abu Dhabi)
|UK South (London)||
UK West (Newport)
Israel Central (Jerusalem)
South Africa Central (Johannesburg)
Germany Central (Frankfurt)
|UK West (Newport)||UK South (London)|
|US Midwest (Chicago)||
US East (Ashburn)
US West (Phoenix)
|US East (Ashburn)||
US Midwest (Chicago)
US West (Phoenix)
|US West (Phoenix)||
US East (Ashburn)
US Midwest (Chicago)
US West (San Jose)
Mexico Central (Queretaro)
|US West (San Jose)||US West (Phoenix)|
Required IAM Service Policy
To use Oracle Cloud Infrastructure, you must be granted security access in a policy by an administrator. This access is required whether you're using the Console or the REST API with an SDK, CLI, or other tool. If you get a message that you don’t have permission or are unauthorized, verify with your administrator what type of access you have and which compartment to work in.
For administrators: The policy in Let users create, manage, and delete file systems allows users to create and manage file systems and replications.
A more restrictive policy that only allows creation and management of replications for a specific source and target file system:
Allow group Managers to manage replications in tenancy Allow group Managers to manage file-systems in tenancy
If you're new to policies, see Getting Started with Policies and Common Policies.