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FSR
FSR(File level sync and replication) is a file-level, host-based network-wired replication solution and real-time backup for critical enterprise data.
Users can easily specify replication targets at the file and directory level, and can create flexible replication environments with various configurations such as 1:1, 1:N, N:1 and shared replication. The replication deployment process enables live migration even in a pre-built environment without any downtime in terms of service operations. It also provides various functions such as automatic split brain detection that can occur during redundancy, backup of deleted data, compression/encryption, and snapshot.
Main Features
Synchronization
Before FSR performs data replication is performed, the FSR it copies the entire data from the source node to the target node to match the data of on the source and the target. This process is called synchronization.
When performing the initial synchronization is performed, the entire data is synchronized . Howeverto the target, but if resynchronization is necessary required after the initial synchronization is completed once, the partial synchronization is efficiently performed by incremental synchronization only for changes in the change of the source node data to achieve efficient synchronization. Resynchronization is performed when the replication network is re establishednormalized, such as when the replication network connection is disconnected and reconnected during replication, or when the a node is stopped (rebooted) and then reconnected. In other words, after the initial synchronization, FSR automatically performs incremental partial synchronization whenever necessarysynchronization is required.
Synchronization can also be performed done manually by user intervention, such as synchronization commands and synchronization schedule settings.
Replication
Even when synchronization is complete or synchronization is in progress, the data on the source node can be changed in real time. This behavior of reflecting these changes in real time from the source node to the target node is called replication. Synchronization and replication play the same role in reflecting data from source to target, but FSR separates them.
Replication is divided into synchronous and asynchronous, depending on how replication is handled.
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the user, for example, by issuing a sync command, configuring periodic synchronization, etc.
Replication
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The behavior of reflecting changes to data to a real-time target is called replication. Changes to data are made even while synchronization is in progress, meaning that synchronization and replication are handled separately. Although synchronization and replication can be said to do the same thing in terms of reflecting data from the source to the target, FSR keeps them separate.
Replication is categorized as synchronous or asynchronous depending on how it is handled.
- Synchronous methods fully guarantee target congruency by reflecting write I/O
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- from one disk to
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- the source and target disks simultaneously and then completing it.
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- However, there are performance limitations in deploying performance-critical services in a synchronous manner because the replication response performance of the target node affects the local I/O latency
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- performance
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- .
- The asynchronous
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- approach considers replication complete when disk write I/
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- Os are reflected locally and
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- replication data is copied to the transfer buffer. This
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- method does not fully guarantee target congruency because some data that has been in the process of buffering replication may be lost if there is a sudden node failure on the source side. However, it guarantees high performance with no impact on local I/O latency and is used to build distant replication without transmission bandwidth constraints.
FSR supports asynchronous replication by default. Asynchronous replication performs internal buffering to minimize the impact of local I/O delayslatency, so and the size of the buffer buffers used must should be set appropriately for your operating environment. The buffer is Buffers are provided as a memory buffer buffers and a file bufferbuffers, and its their size is determined based on the contents of the buffer configuration in Configurationsset within the available memory and disk limits of the system.
Online File Verification
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In addition to performing real-time replication to the target node, it provides a snapshot function to back up data at a specific point in time to a separate space. For more information, refer to 5.5. Snapshot
HA/DR support
FSR provides CLI and Rest-API for HA / DR integration. Refer to System Manual, Appendix B. FSR Interface Guide.
Terms
Node
A generic term for devices connected to a network, of which computer nodes are called hosts. Normally, node and host tend to be used without distinction. In this manual, node is used with the same meaning without distinguishing from host.
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