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You can also use the command line interface to initiate Copy Services commands
from your open host system. See the IBM Enterprise Storage Server Host Systems
Attachment Guide for more information on the command-line interface.
A FlashCopy relationship is between CKD volumes or FB LUNs. This relationship
exists from the time you initiate a FlashCopy operation:
v Until the ESS copies all data from the source to the target, or
v Until you withdraw the FlashCopy relationship
For System/390 hosts, the FlashCopy feature provides instant replication of a full
CKD volume.
After a FlashCopy operation, track images on the source volumes and the target
volumes are independently available for data read and write operations. You can
use FlashCopy to create copies for:
v Disaster recovery
v Business intelligence applications
v Use in a test environment
v Instant checkpoints
Note: For System/390 hosts you can use TSO to invoke these functions for MVS
While your critical applications continue using the source volume, you can define
and initiate a FlashCopy from the ESS Specialist Web interface. Once you have
defined and initiated the target volume, it is available to you for tasks such as
asynchronous backup.
See "FlashCopy and PPRC restrictions for open system hosts" on page 18 for
additional information about FlashCopy.
Peer-to-Peer Remote Copy
The Peer-to-Peer Remote Copy (PPRC) feature allows synchronous copying of a
physical volume (the source) on one storage server to another volume (the target)
on a second storage server. PPRC ensures write operations on both local and
remote copies. The ESS supports PPRC on System/390 hosts and open system
hosts (SCSI or fibre channel). PPRC is not supported on AS/400 host systems.
Note: A PPRC target cannot be accessed until the PPRC relationship is ended,
If a volume is reserved by host application software it cannot be used as a
secondary volume for PPRC.
You need to connect the ESSNet to both the primary and recovery sites through
your LAN to initiate PPRC operations for SCSI and fibre-channel attached hosts.
v The primary storage server (application site) establishes the paths and links to a
v From the primary host, the I/O operation to the secondary storage server is
that is the target volume is no longer part of a PPRC pair.
secondary storage server (recovery site). The primary storage server also
manages the synchronous copying of the volume from the primary site to the
secondary site. The remote secondary server can be up to 103 km from the
primary server.
transparent.
™
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17
Chapter 1. Introduction
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