HP StoreAll Storage - Manual (Page 179)

Run-once replication. This method replicates a single directory sub-tree or an entire file system from
the source file system to the target file system. Run-once is a single-pass replication of all files and
subdirectories within the specified directory or file system. All changes that have occurred since
the last replication task are replicated from the source file system to the target file system. File
systems specified as the replication source or target must exist. If a directory is specified as the
replication source, the directory must exist on the source cluster under the specified source file
system.
NOTE: Run-once can also be used to replicate a single software snapshot. This must be done on
the GUI.
You can replicate to a remote cluster (an intercluster replication) or the same cluster (an intracluster
replication).
Using intercluster replications
Intercluster configurations can be continuous or run-once:
•
Continuous: asynchronously replicates the initial state of a file system and any changes to it.
Snapshots cannot be replicated.
•
Run-once: replicates the current state of a file system, folder, or file system snapshot.
The examples in the configuration rules use three StoreAll clusters: C1, C2, and C3:
•
C1 has two file systems, c1ifs1 and c1ifs2, mounted as /c1ifs1 and /c1ifs2.
•
C2 has two file systems, c2ifs1 and c2ifs2, mounted as /c2ifs1 and /c2ifs2.
•
C3 has two file systems, c3ifs1 and c3ifs2, mounted as /c3ifs1 and /c3ifs2.
In the examples, <cluster name>:<target path> designates a replication target such as
C1:/c1ifs1/target1
.
The following rules apply to intercluster replications:
•
Remote replication is not supported between 6.1.x and 6.2 clusters in either direction if Express
Query is enabled on the 6.2 cluster.
•
Only one continuous Remote Replication task can run per file system. It must replicate from
the root of the file system; you cannot continuously replicate a subdirectory of a file system.
•
A continuous Remote Replication task can replicate to only one target cluster.
•
Replication targets are directories in a StoreAll file system and can be:
The root of a file system such as /c3ifs1. ◦
◦ A subdirectory such as /c3ifs1/target1.
Targets must be explicitly exported using CRR commands to make them available to CRR
replication tasks.
•
A subdirectory created beneath a CRR export can be used as a target by a replication task
without being explicitly exported in a separate operation. For example, if the exported target
is /c3ifs1/target1, you can replicate to folder /c3ifs1/target1/subtarget1 if the
folder already exists.
•
Directories exported as targets cannot overlap. For example, if C1 is replicating /c1ifs1 to
C2:/c2ifs1/target1
, C3 cannot replicate /c3ifs1 to C2:/c2ifs1/target1/target2.
•
A cluster can be a target for one replication task at the same time that it is replicating data to
another cluster. For example, C1 can replicate /c1ifs1 to C2:/c2ifs1/target1 and C2
can replicate /c2ifs2 to C1:/c1ifs2/target2, with both replications occurring at the
same time.
Overview 179