Draft Document for Review February 7, 2020 4:43 pm 8464ch12_Performance.fm GLYPH<SM590000> Chosen replication mode  GLYPH<SM590000> Defined number of concurrent copy tasks  GLYPH<SM590000> Number of remote write/read operations GLYPH<SM590000> Cloud attach configuration GLYPH<SM590000> DS8000 Object Store configuration 12.7.1 Mixing different grid link adapters and traffic from Cloud attach or  DS8000 object store considerations 12.7.2 Bandwidth and quality of the provided network  Chapter 12. Performance considerations  723 GLYPH<SM590000> Latency between the TS7700s GLYPH<SM590000> Network efficiency (packet loss, packet sequencing, and bit error rates) GLYPH<SM590000> Network switch capabilities GLYPH<SM590000> Flow control to pace the data from the TS7700s GLYPH<SM590000> Inter-switch link (ISL) capabilities, such as flow control, buffering, and performance GLYPH<SM590000> Network traffic quality of service (QoS) capabilities Cache bandwidth is always an influencing factor and was described in 12.6, “Cache  throughput and cache bandwidth” on page 718. Different grid link adapter types cannot be included in a single cluster. However, a situation  can exist in a grid in which some clusters are connected to the grid link by using 10 GB  adapters, and other clusters are connected by using 1 GB adapters. This situation is  especially true for migration or upgrade scenarios. In the TS7700 grid, a 1:1 relationship exists between the primary and primary adapters, and  the secondary and secondary adapters. Because of this relationship, in a mixed environment  of 2*10 GB and 4*1 GB adapters, the clusters with the 4*1 GB links cannot use the full speed  of the installed grid link adapters.  In the current TS7700C configuration, grid link adapters are shared by communication traffic  between clusters  and  between a cluster and cloud. When cloud traffic is high (especially in  on-premises Object Storage), grid link adapters are highly used. This issue might affect the  grid link data replication throughput between clusters in the grid. Also, if you configure DS8000 Object Store function that connects to DS8000, data traffic  between DS8000 and TS7700 might affect the grid link data replication throughput.  Therefore, carefully plan to fit the performance requirements. You can control DFSMShsm  data migration from DS8000 to TS7700 by setting the migration schedule in the z/OS side to  avoid the grid link adapter competition between usual tape I/O and object store traffic. The network between the TS7700s must have sufficient bandwidth to account for the total  replication traffic. If you are sharing network switches among multiple TS7700 paths or with  other network traffic, the total bandwidth on that network must be sufficient to account for all  of the network traffic.  The TS7700 uses the TCP/IP protocol for moving data between each cluster. In addition to  the bandwidth, other key factors affect the throughput that the TS7700 can achieve. The  following factors directly affect performance: The TS7700s attempt to drive the network links at the full 1-Gb rate for the two or four 1-Gbps  links, or at the highest possible load at the two 10-Gbps links, which might be much higher  than the network infrastructure can handle. The TS7700 supports the IP flow control frames  to have the network pace the rate at which the TS7700 attempts to drive the network. 