HP StorageWorks Storage Mirroring for Linux User's Guide (T2558-96317, June 2009)

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Storage Mirroring operations
Storage Mirroring performs four basic types of operations.
 Mirroring—The initial copy or subsequent resynchronization of selected data
 Replication—The on-going capture of byte-level file changes
 Failure monitoring and failover—The ability to monitor and stand-in for a server, in the event
of a failure
 Restoration—A mirror of selected data from the target back to the source
Mirroring
Mirroring is the process of transmitting user-specified data from the source to the target so that an
identical copy of data exists on the target. When Storage Mirroring initially performs mirroring, it
copies all of the selected data, including file attributes and permissions. Mirroring creates a
foundation upon which Storage Mirroring can efficiently update the target server by replicating only
file changes.
If subsequent mirroring operations are necessary, Storage Mirroring can mirror specific files or blocks
of changed data within files. By mirroring only files that have changed, network administrators can
expedite the mirroring of data on the source and target servers.
Mirroring has a defined end point - when all of the selected files from the source have been
transmitted to the target. When a mirror is complete, the target contains a copy of the source files
at that point in time.
Source Target
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All files can be
Checksums can
calculate blocks to
Different files can
be mirrored
New files are mirrored
Identical files are
not mirrored
Flexible mirroring options allow you to choose
which files are mirrored from the source to the target.
mirrored
be mirrored