Based on available measurements and experiences with the ESS 800 we recommend you should plan no more than four iSeries I/O adapters to one host port in the DS6000.
For a current list of switches supported under OS/400, refer to the iSeries Storage Web site at:
Migration
For many iSeries customers, migrating to the DS6000 will be best achieved using traditional Save/Restore techniques. However, there are some alternatives you may wish to consider.
OS/400 mirroring
Although it is possible to use OS/400 to mirror the current disks (either internal or external) to a DS6000 and then remove the older disks from the iSeries configuration, this is not recommended because both the source and target disks must initially be unprotected. If moving from internal drives, these would normally be protected by
Once an external logical volume has been created, it will always keep its model type and be either protected or unprotected. Therefore, once a logical volume has been defined as unprotected to allow it to be the mirror target, it cannot be converted back to a protected model and therefore will be a candidate for all future OS/400 mirroring, whether you want this or not. See Table
Metro Mirror and Global Copy
Depending on the existing configuration, it may be possible to use Metro Mirror or Global Copy to migrate from an ESS to a DS6000 (or indeed, any combination of external storage units which support Metro Mirror and Global Copy). For further discussion on Metro Mirror and Global Copy, see 15.2.2,
Here, the iSeries has its internal Load Source Unit (LSU) and possibly some other internal drives. The ESS provides additional storage capacity. Using Metro Mirror or Global Copy, it is possible to create copies of the ESS logical volumes in the DS6000.
When ready to migrate from the ESS to the DS6000, you should do a complete shutdown of the iSeries, unassign the ESS LUNs and assign the DS6000 LUNs to the iSeries. After IPLing the iSeries, the new DS6000 LUNs will be recognized by OS/400, even though they are different models and have different serial numbers.
Note: It is important to ensure that both the Metro Mirror or Global Copy source and target copies are not assigned to the iSeries at the same time because this is an invalid configuration. Careful planning and implementation is required to ensure this does not happen, otherwise unpredictable results may occur.
Appendix B. Using the DS6000 with iSeries 357
