HP StoreAll Storage - Manual (Page 122)

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 X9000 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, : designates a replication target such as
C1:/c1ifs1/target1
.
The following rules apply to intercluster replications:
•
Only one continuous Remote Replication task can run per file system. It must replicate from
the root of the filesystem; 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 an X9000 file system and can be:
The root of a filesystem 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.
•
A cluster can be a target for multiple replication tasks. For example, C1 can replicate /c1ifs1
to C3:/c3ifs1/target1 and C2 can replicate /c2ifs1 to C3:/c3ifs1/target2, with
both replications occurring at the same time.
•
Continuous Remote Replication tasks can be linked. For example:
C1 replicates /c1ifs1 to C2:/c2ifs1/target1. ◦
◦ C2 replicates /c2ifs1/target1 to C3:/c3ifs2/target2.
122 Using remote replication