78 Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1
Global Mirror volumes should have their preferred access nodes evenly distributed between 
the nodes of the clustered systems. Figure 3-11 shows an example of a correct relationship 
between volumes in a Metro Mirror or Global Mirror solution.
Figure 3-11   Correct volume relationship
The back-end storage systems at the replication target site must be capable to handle the 
peak application workload to the replicated volumes, plus the client-defined level of 
background copy, plus any other I/O being performed at the remote site. The performance of 
applications at the local clustered system can be limited by the performance of the back-end 
storage controllers at the remote site. This consideration is especially important for Metro 
Mirror replication.
A complete review must be performed before Serial Advanced Technology Attachment 
(SATA) drives are used for any Metro Mirror or Global Mirror replica volumes. If a slower disk 
subsystem is used as target for the remote volume replicas of high-performance primary 
volumes, the Storwize V7000 cache might not be able to buffer all the writes. The speed of 
writes to SATA drives at the remote site might limit the I/O rate at the local site.
To ensure that the back-end storage can support the data replication workload, you can 
dedicate back-end storage systems to only Global Mirror volumes. You can also configure the 
back-end storage to ensure sufficient quality of service (QoS) for the disks that are used by 
Global Mirror. Alternatively, you can ensure that physical disks are not shared between data 
replication volumes and other I/O.
3.16  SAN boot support
The IBM Storwize V7000 supports SAN boot or start-up for AIX, Microsoft Windows Server, 
and other operating systems. Because SAN boot support can change, check this IBM System 
Storage Interoperation Center (SSIC) web page regularly.