HP Command View EVA Software User Manual

Page 45

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Fibre Channel switches typically offer two types of frame routing between N_Ports:

Source ID/Destination ID (SID/DID) routing, which transfers all exchanges through the fabric
using the same path

Exchange-based routing, which transfers all frames within an exchange using the same path,
but other exchanges may use alternate paths

NOTE:

B-class switches refer to SID/DID protocol as in-order delivery routing. C-class switches

refer to SID/DID protocol as flow-based load balancing . Both switch classes use exchange-based
routing terminology. See the individual switch user guides for configuration details.

The current HP FC Data Replication Protocol (HP-FC) uses multiple exchanges for each data
replication transfer. One or more exchanges are used to transfer data and an additional exchange
is used for command information. The HP-FC Protocol requires all frames within the transfer to be
delivered in order. Therefore, if HP-FC Protocol is used in the fabric, the fabric must use SID/DID
routing.

HP SCSI FC-Compliant Data Replication Protocol (HP SCSI-FC) was developed to take advantage
of the exchange-based routing protocol available in fabric switches. HP SCSI-FC and HP-FC
protocols are available on controller software versions later than 0952xxxx; earlier versions support
only the FC-HP Protocol.

The three options listed in

Figure 6 (page 44)

are as follows:

HP FC Data Replication Protocol. This protocol requires all transfers to be completed in order,
which is accomplished by the proper configuration of the SAN fabric switches for SID/DID.
See the HP P6000 Continuous Access Implementation Guide for specific settings and the
appropriate switch user guides for detailed instructions.

A storage system configured for this protocol successfully creates a DR group only with a
storage system capable of HP-FC, which is the default protocol for controller software versions
0952xxxx and earlier, and is user-selectable in later versions. Fabric misconfiguration with
this protocol selection results in significant performance degradation and possible data integrity
issues on the destination storage system.

HP SCSI FCP Compliant Data Replication Protocol. This protocol supports the transfer of EVA
data replication traffic in a fabric configured for exchange-based or SID/DID routing. The
protocol can take advantage of the exchange-based fabric setting, but is not dependent on
the fabric setting. For the proper configuration of the SAN fabric switches for Exchange, see
the HP P6000 Continuous Access Implementation Guide; for specific settings, see the
appropriate switch user guides for detailed instructions.

Either. This selection should be used when the SAN contains storage systems running both
HP-FC and HP SCSI-FC protocols. The Either selection allows storage systems only capable of
HP-FC to successfully create DR groups with the storage systems running controller software
version later than 0952xxxx. This facilitates the migration of data from older to newer storage
systems. The HP-FC protocol is dependent on the fabric configuration being set for SID/DID
routing. The same fabric considerations noted in the HP-FC option apply to the Either selection
as well.

HP P6000 Continuous Access software

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