IBM V7000 Introduction And Implementation Manual page 435

With IBM Flex System V7000 Storage Node, customers might want to use the Global
Mirror capability which enables them to have a low bandwidth link between sites. This
capability is known as Global Mirror with Change Volumes and should have Change
Volumes defined for both the source and target volumes when used.
This capability provides options to help administrators balance network bandwidth
requirements and RPO times for applications, helping reduce operation costs for disaster
recovery solutions. Remote mirroring supports higher RPO times by allowing the data at
the disaster recovery site to get further out of sync with the production site if the
communication link limits replication, and then approaches synchronicity again when the
link is not as busy. This low bandwidth remote mirroring uses space-efficient FlashCopy
targets as sources in remote copy relationships to increase the time allowed to complete a
remote copy data cycle.
Licensing for Remote Copy
To authorize use of remote copy capabilities of IBM Flex System V7000 Storage Node, you
must purchase a feature license for IBM Flex System V7000 Remote Mirroring Software. This
license is based on the quantity of enclosures that are authorized for the feature. This topic is
detailed in 2.4, "IBM Flex System V7000 Storage Node licensing" on page 46.
Remote Copy configuration limits
Table 9-4 lists the Remote Copy configuration limits.
Table 9-4 Remote Copy configuration limits
Parameter
Number of Remote Copy consistency groups
per cluster
Number of Remote Copy relationships
per consistency group
Number of Remote Copy relationships
per I/O group
Total Remote Copy volume capacity
per I/O group
SAN planning for Remote Copy
The following section describes planning guidelines for a SAN with Remote Copy.
Zoning recommendation
Node canister ports on each IBM Flex System V7000 Storage Node must be able to
communicate with each other in order for the partnership creation to be performed. These
ports must be visible to each other on your SAN. Proper switch zoning is critical to facilitating
inter-cluster communication.
The SAN zoning recommendation is as follows:
For each node canister, exactly two Fibre Channel ports should be zoned to exactly two
Fibre Channel ports from each node canister in the partner cluster.
If dual-redundant inter-switch links (ISLs) are available, then the two ports from each node
should be split evenly between the two ISLs, that is, exactly one port from each node
canister should be zoned across each ISL.
Value
256
8,192
2,048
1024 TB (This limit is the total capacity for all
master and auxiliary volumes in the I/O group.)
Chapter 9. IBM Flex System V7000 Storage Node Copy Services
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