HP P6000 manual Replicating storage

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 43) 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.

An array configured for this protocol successfully creates a DR group only with an array 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 array.

•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 arrays running both HP-FC and HP SCSI-FC protocols. The Either selection allows arrays only capable of HP-FC to successfully create DR groups with the arrays running controller software version later than 0952xxxx.

This facilitates the migration of data from older to newer arrays. 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.

44 Replicating storage