Chapter 3. Planning 81
– 2076-92F
– 2076-A9F 
The control enclosures can connect to 8 Gbps and 16 Gbps SAN switches. With an optional 
10 Gbps Ethernet card to 10 Gbps Ethernet switch (for iSCSI traffic) and FCoE switches.
Model 2076-624 with 25 Gb Ethernet card can be used for RDMA (iSER). For more 
information, see 3.7.4, “iSCSI Extensions for RDMA (iSER)” on page 62.
3.19.2  Back-end storage subsystems
When connecting a back-end storage subsystem to IBM Storwize V7000, follow these 
guidelines:
/SM590000Connect all storage ports to the switch up to a maximum of 16, and zone them to all of the 
Storwize V7000 ports. 
/SM590000Zone all ports on the disk back-end storage to all ports on the Storwize V7000 nodes in a 
clustered system. 
/SM590000Ensure that you configure the storage subsystem LUN-masking settings to map all LUNs 
that are used by the Storwize V7000 to all the Storwize V7000 WWPNs in the clustered 
system. 
The Storwize V7000 is designed to handle many paths to the back-end storage. 
In most cases, the Storwize V7000 can improve performance, especially of mid-sized to 
low-end disk subsystems, older disk subsystems with slow controllers, or uncached disk 
systems, for the following reasons: 
/SM590000The Storwize V7000 can stripe across disk arrays, and it can stripe across the entire set of 
configured physical disk resources.
/SM590000The Storwize V7000 control enclosure 2076-524 has 32 GB of cache and 2076-624 has 
32 GB of cache (upgradeable to 64 GB).
/SM590000The Storwize V7000 can provide automated performance optimization of hot spots by 
using flash drives and Easy Tier. 
The Storwize V7000 large cache and advanced cache management algorithms also allow it 
to improve the performance of many types of underlying disk technologies. The Storwize 
V7000 capability to asynchronously manage destaging operations that are incurred by writes 
while maintaining full data integrity can be important in achieving good database 
performance. 
Because hits to the cache can occur in the upper (Storwize V7000) and the lower (back-end 
storage disk controller) level of the overall system, the system as a whole can use the larger 
amount of cache wherever it is located. Therefore, Storwize V7000 cache also provides more 
performance benefits for back-end storage systems with extensive cache banks. 
Also, regardless of their relative capacities, both levels of cache tend to play an important role 
in enabling sequentially organized data to flow smoothly through the system. 
However, Storwize V7000 cannot increase the throughput potential of the underlying disks in 
all cases. Performance benefits depend on the underlying storage technology and the 
workload characteristics, including the degree to which the workload exhibits hotspots or 
sensitivity to cache size or cache algorithms.