Your suggestion to replace the DS8000 with the V7000 in analogy is like installing motorcycle wheels on BMW 7 series.
There is a huge difference in functionality, performance, scalability and availability between a mid-range and high-end storage. FICON interface doesn't convert storage subsystem for mainframe storage.
Some (not all) of the System z features:
* High Performance FICON (zHPF) - zHPF is high-performance data transfer. It has four functions and each function requires cooperation between the System z server and the storage system. Selected zHPF functions are: multitrack (allow reading or writing more than two tracks worth of data by a single transport mode operation), extended distance, format writes, QSAM, BSAM, BPAM, and DB2 list prefetch.
* Parallel Access Volumes (PAV) and HyperPAV are features which allow using multiple devices or aliases to address a single ECKD disk device.
* Performance - I/O priorities Supports "importance" and "achievement" information provided by z/OS Workload Manager
* Performance - DB2 Specialized cache algorithm to optimize DB2 list prefetch operations
* Performance – IMS Enhanced performance for IMS write-ahead data set (WADS)
* Performance - zDAC Supports an optimization to improve performance of z/OS Discovery and AutoConfiguration (zDAC)
* Volume Management Supports dynamic volume expansion for standard (thick) 3390 volumes , Extended Address Volumes (EAV) –supports 3390 volumes up to 1TB capacity
* Multiple Readers for IBM System Storage z/OS Global Mirror - improved performance and fewer disruptions under heavy write load conditions and as a result experience significantly better performance in particular in busy z/OS environments.
* GDPS and HyperSwap support
Since October 2007 IBM has accelerated its development rate, offering enhancements at the fastest pace in the industry. Examples of major enhancements include IBM’s introduction of RAID-6 in August ‘08, high-performance FICON for System z in October ‘08, full-disk encryption and a solid-state drive (SSD) option in February ’09, and thin provisioning July ‘09.
In April 2010 IBM announced and delivered the IBM System Storage Easy Tier which automates data placement within the DS8000 subsystem. This includes the ability for the system to automatically and non-disruptively relocate data (at the extent level) across drive tiers, and the ability to manually relocate full volumes. This was the first sub-LUN automated data movement.
IBM's System Storage DS8870 series is a stable multiplatform high-end storage system . IBM, which ten, fifteen years ago lost some of its high-end disk enterprise storage market share, has managed an impressive come-back.
There are plenty synergies in operation between System z mainframes and DS8870 subsystems in particular in Disaster Recovery and Business Continuity but also with DB2, etc.
The operation GIU, ported from XIV delivers the most user friendly functionalities in the industry.
Full redundancy, non-disruptive upgrades and maintenance, hot-swappable components, pre-emptive soft error detection and online microcode changes ensure high availability and data integrity. The advanced remote data replication techniques enable any scheme of disaster recovery deployments.
The DS8000 is a leader in SPC-1, SPC-2 (non-SSD) performance benchmarks.