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The Source Cluster section is used to specify where the source data resides that will be replicated to the target cluster, as displayed in the following figure.
Note: Specifying the source cluster directory as /ifs/data is not supported. Create subdirectories for replication under /ifs/data. The /ifs/data directory includes the Isilon_Support folder where cluster logs are written and is the path cited for placing installation files. Replicating the /ifs/data directory as root, causes issues during failover and failback.
A SyncIQ policy by default includes all files and folders under the specified root directory. Optionally, directories under the root directory can be explicitly included or excluded.
Note: As a best practice, avoid overlapping source directory SyncIQ policies with differing retention times to prevent nested snapshots.
As source and target cluster replication directories are specified, consider the impacts on understanding where data originated through failovers and failbacks. Also, if the data is replicated across multiple clusters, understanding the origin of the data becomes further complicated. The best practice is to use the cluster name, a numerical access zone number, and a directory. For example, Access Zone 1 maps to /ifs/data/clustername/az1/<data directories>, Access Zone 2 maps to /ifs/data/clustername/az2/<data directories>, as shown in the following figure. A root-based path with this delineation provides data separation and multitenancy, maintains the Unified Permission model, and makes SyncIQ failover and failbacks easier. For more information about access zones, see the Access zones best practices section in the PowerScale: Network Design Considerations white paper. For more information about the Unified Permission Model, see the PowerScale OneFS Authentication, Identity Management, and Authorization white paper.
If any directories are explicitly included in the policy configuration, the system synchronizes only those directories and their included files to the target cluster. If any directories are explicitly excluded, those directories and any files contained in them are not synchronized to the target cluster.
Any directories explicitly included must reside within the specified root directory tree. Consider a policy with the root directory /ifs/data/cluster1 and explicitly include the /ifs/data/cluster1/media directory because it is under /ifs/data/cluster1. When the associated policy runs, only the contents of the /ifs/data/cluster1/media directory would be synchronized to the target cluster. However, the directory /ifs/data/projects is not included because it is not part of the /ifs/data/cluster1 tree.
If a directory is explicitly excluded within the specified root directory, all the contents of the root directory except for the excluded directory will be synchronized to the target cluster.
If both included and excluded directories are specified, every explicitly included directory will be replicated, and every other file, or directory, under the exclude directory, will be excluded from the replication dataset.
For example, consider a policy with the root directory /ifs/data/cluster1, and the following directories explicitly included and excluded:
Explicitly included directories:
/ifs/data/cluster1/media/music
/ifs/data/cluster1/media/movies
Explicitly excluded directories:
/ifs/data/cluster1/media/music/working
/ifs/data/cluster1/media
In this example, all directories below /ifs/data/cluster1/media are excluded except for those directories that are specifically included. Therefore, directories such as /ifs/data/cluster1/media/pictures, /ifs/data/cluster1/media/books, /ifs/data/cluster1/media/games are excluded because of the exclude rule. The directory and all subdirectories of /ifs/data/cluster1/media/music will be synchronized to the target cluster, except for the directory /ifs/data/cluster1/media/music/working.
Note: Depending on the include and exclude directory configuration, SyncIQ performance may be affected. If possible, avoiding an include and exclude configuration simplifies policy configuration and ensures that performance is not degraded. As a best practice, test the impacts of include and exclude policies in a lab environment before updating a production cluster. Alternatively, multiple policies can be configured with different source directories rather than creating a single policy with includes and excludes.