IBM DS8000 manual Hardware- or microcode-based migration

This requires an adequate bandwidth for the connectivity between the disk storage servers to the system image which hosts the SDMs. Because XRC in migration mode stores the data through, it mainly requires channel bandwidth and SDM tends to monopolize its channels. Therefore, the approach with dedicated channel resources is an advantage over a shared channel configuration and would almost not impact the application I/Os.

XRC requires disk storage subsystems which support XRC primary volumes through the microcode. Currently only IBM- or HDS-based controllers support XRC as a primary or source disk subsystem. As an exception, this does not apply to the IBM RVA storage controller, which does not support XRC as a primary XRC device. Also, EMC does not provide XRC support at the XRC primary site.

14.2.3 Hardware- or microcode-based migration

Hardware- and microcode-based migration through remote copy is usually only possible between like hardware, so using remote copy through microcode is not possible with different disks from vendor A at the source site and disks from vendor B at the target site. Therefore, we discuss only what is possible for IBM disk storage servers using remote copy or Peer-to-Peer Remote Copy (PPRC) and its variations.

Remote copy approaches with Global Mirror, Metro Mirror, Metro/Global Copy, and Global Copy allow the primary and secondary site to be any combination of ESS 750s, ESS 800s and DS6000s or DS8000s.

Although IBM did not announce support of Metro/Global Copy for the DS8000, it will work for certain migration scenarios, as outlined in the next section, when the DS8000 disk server receives the data as the Global Copy secondary disk server. In this case the DS8000 holds the Global Copy secondary volumes within a plain Global Copy relationship with the respective ESS as the Global Copy primary disk server.

Bridge from ESCON to FICON with Metro/Global Copy

The ESS Model E20 and Model F20 do not support PPRC over Fibre Channel links, but only PPRC based on PPRC ESCON links. In contrast, the newly announced disk storage servers support only PPRC over Fibre Channel links and do not support PPRC ESCON links. The ESS Model 800 supports both PPRC link technologies.

			FICON
	ESCON	Intermediate ESS 800	DS8000
	PPRC
			PPRC
ESS F20	ESCON
			FCP
			Links
	Links	Cascading
ESS F20
	Metro Mirror		Global Copy
		Metro/Global Copy

Figure 14-4 Intermediate ESS 800 used to migrate data with PPRC over ESCON from older models

302DS8000 Series: Concepts and Architecture