HP StorageWorks 2/24 FW 07.00.00/HAFM SW 08.06.00 McDATA Products in a SAN Env - Page 181

Extended-Distance Operational Modes, Extended-Distance, Operational Modes

Page 181 highlights

Implementing SAN Internetworking Solutions 4 • Reliability - Local storage traffic requires high-reliability communication and is intolerant of data loss, out-of-order packet receipt, or data retransmission. WANs typically provide besteffort communication service and rely on upper-level protocols for end-to-end transport. Because of these differences, a protocol conversion approach is usually required to integrate Fibre Channel SAN traffic over a geographically-dispersed network. Refer to SAN Extension Transport Technologies for detailed information about native FCP distance extension or protocol conversion. Other BC/DR requirements vary, depending on budget, data type, data volume, business situation, and SAN applications. Analyze and understand these business requirements prior to selecting an operational mode (described in Extended-Distance Operational Modes) and transport technology (described in SAN Extension Transport Technologies) that best support the SAN distance-extension strategy. In particular, consider: • Data priority - Not all data is critical to immediate business resumption. Prioritize and categorize data as mission-critical, secondary, or only to be retained for legal purposes. • Recovery time objective (RTO) - The RTO is the time required to restore the data and applications following an outage or disaster. The loss of revenue from suspended business operations drives this objective. • Recovery point objective (RPO) - The RPO is the time between backup points and defines how far out of date a backup copy can be after a failure. The data rate of change and cost of destroyed data (between the last backup and a disaster) drive this objective. • Distance - The distance between a data center and replication site is proportional to RTO and RPO times. As distance between sites increases, time required to perform backup and restore operations also increases. Extended-Distance Operational Modes A primary component of business continuance and disaster recovery is data replication to an alternative safe location. Extended-distance operational modes are: Implementing SAN Internetworking Solutions 4-37

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4
Implementing SAN Internetworking Solutions
4-37
Implementing SAN Internetworking Solutions
Reliability -
Local storage traffic requires high-reliability
communication and is intolerant of data loss, out-of-order packet
receipt, or data retransmission. WANs typically provide best-
effort communication service and rely on upper-level protocols
for end-to-end transport.
Because of these differences, a protocol conversion approach is
usually required to integrate Fibre Channel SAN traffic over a
geographically-dispersed network. Refer to
SAN Extension Transport
Technologies
for detailed information about native FCP distance
extension or protocol conversion.
Other BC/DR requirements vary, depending on budget, data type,
data volume, business situation, and SAN applications. Analyze and
understand these business requirements prior to selecting an
operational mode (described in
Extended-Distance Operational Modes
)
and transport technology (described in
SAN Extension Transport
Technologies
) that best support the SAN distance-extension strategy. In
particular, consider:
Data priority -
Not all data is critical to immediate business
resumption. Prioritize and categorize data as mission-critical,
secondary, or only to be retained for legal purposes.
Recovery time objective (RTO) -
The RTO is the time required to
restore the data and applications following an outage or disaster.
The loss of revenue from suspended business operations drives
this objective.
Recovery point objective (RPO) -
The RPO is the time between
backup points and defines how far out of date a backup copy can
be after a failure. The data rate of change and cost of destroyed
data (between the last backup and a disaster) drive this objective.
Distance -
The distance between a data center and replication site
is proportional to RTO and RPO times. As distance between sites
increases, time required to perform backup and restore operations
also increases.
Extended-Distance
Operational Modes
A primary component of business continuance and disaster recovery
is data replication to an alternative safe location. Extended-distance
operational modes are: