The basic

bsr synchronizes and replicates host the volumes within a fail-over of hosts in a cluster in real time over the network to make them redundant.

Synchronization and Replication

To replicate, volume data on both hosts must first match. Data is copied To achieve this, bsr performs a process of copying data from the source to the target in disk block units over the network. This process using disk blocks as a unit, which is called synchronization. Only when

Once synchronization is complete does it move to the replication state.Replication is an operation that reflects , both volumes will be in a completely identical state, and if data changes occur on the source side, only the changes will be reflected to the target side to maintain the consistency of both volumes.

Here, when data on the source side changes, the operation of reflecting the change in real time to the target side when data on the source side is changed by write I/Ocalled replication. Synchronization operates slowly in the background, while replication occurs quickly in the context of local I/O.

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• A resource is a replication group consisting of one or more volumes that share a common replication stream, which . bsr ensures the consistency of all volumes within the a resource.

• A volume is described as a single device and is specified by a drive letter in Windows.

• A replica set requires one volume for data replication and a separate volume to store metadata associated with the volume. The meta volume is used to store and manage internal information for replication.

  • Metadata is divided into external and internal meta types based on where it is stored. For example, if the metadata is located on the disk of the volume being replicated, it is internal meta; if it is located on another device or another disk, it is external meta.

  • External meta types have an advantage over internal meta in terms of performance because replication I/O and meta data writing can be performed simultaneously during operation, and the I/O performance of the meta disk directly affects replication performance, so it is recommended to configure it with a high-performance disk as much as possible.

  • The volume for the meta should not be formatted with a filesystem like NTFS and should be configured as RAW.

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