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SAS migration on the Storwize V5010 and Storwize V5030 systems requires the purchase of a pair of optional SAS adapter cards. SAS migration on V5020 can be performed without an adapter card by using the onboard SAS host attachment ports. 

Table 7-1 lists the requirements for each model. 

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## 7.3.3 Overview of the storage migration wizard 

Consider the following points regarding the storage migration wizard process: 

GLYPH<SM590000> Typically, storage systems segregate storage into many Small Computer System Interface (SCSI) LUs that are presented to hosts through a Fibre Channel SAN. Storage can also be presented through direct SAS attachment to a host. In general, the steps to migrate either one of these storage systems are the same. 

GLYPH<SM590000> Input/output (I/O) to the Logical Unit Numbers (LUN) must be stopped and changes must be made to the mapping of the storage system LUs and to the SAN fabric zoning or SAS connectivity so that the original LUs are presented directly to the Storwize V5000 Gen2 and not to the hosts. Storwize V5000 Gen2 discovers the external LUs as unmanaged (not a member of any storage pools) managed disks (MDisks). 

GLYPH<SM590000> The unmanaged MDisks are then imported to the Storwize V5000 Gen2 as image mode MDisks and placed in a storage pool. This storage pool is now a logical container for the externally attached LUs. 

GLYPH<SM590000> Each volume has a one-to-one mapping with an image mode MDisk. From a data perspective, the image mode volume represents the SAN-attached LUs exactly as they were before the import operation. The image mode volumes are on the same physical drives of the storage system and the data remains unchanged. Storwize V5000 Gen2 presents active images of the SAN-attached LUs and it acts as a proxy. 

GLYPH<SM590000> You must remove the storage system multipath device driver from the hosts. Then, configure the hosts for the Storwize V5000 Gen2 attachment. If you are migrating over Fibre Channel, further zoning changes are made for host-to-V5000 Gen2 SAN connections. The Storwize V5000 Gen2 hosts are defined with worldwide port names (WWPNs) and the volumes are mapped to the hosts. After the volumes are mapped, the hosts discover the Storwize V5000 Gen2 volumes through a host rescan or reboot operation. 

GLYPH<SM590000> The Storwize V5000 Gen2 volume mirror operations are then initiated. The image mode volumes are mirrored to generic volumes. The mirrors are online migration tasks, which means that a defined host can still access and use the volumes during the mirror synchronization process. 

GLYPH<SM590000> After the mirror operations are complete, the volume mirror relationships and the image mode volumes are removed. The other storage system LUs are migrated and the now redundant existing storage can be retired or reused elsewhere. 

