Chapter 2. System overview 37
Bridgeworks SANSlide technology, which is integrated with the IBM Storwize family, requires 
no separate appliances and so requires no extra cost and no configuration steps. It uses 
artificial intelligence (AI) technology to transmit multiple data streams in parallel, adjusting 
automatically to changing network environments and workloads. 
SANSlide improves network bandwidth utilization up to 3x. Therefore, customers can deploy 
a less costly network infrastructure, or take advantage of faster data transfer to speed 
replication cycles, improve remote data currency, and enjoy faster recovery.
2.5.24  IBM Storwize V7000 copy services
IBM Spectrum Virtualize supports the following copy services:
/SM590000Synchronous remote copy (Metro Mirror)
/SM590000Asynchronous remote copy (Global Mirror)
/SM590000FlashCopy (Point-in-Time Copy)
/SM590000Transparent Cloud Tiering
Copy services functions are implemented within a single IBM Storwize V7000 or between 
multiple members of the IBM Spectrum Virtualize family. The Copy Services layer sits above 
and operates independently of the function or characteristics of the underlying disk 
subsystems that are used to provide storage resources to an IBM Storwize V7000.
2.5.25  Synchronous or asynchronous remote copy
The general application of remote copy seeks to maintain two copies of data. Often, the two 
copies are separated by distance, but not always. The remote copy can be maintained in 
synchronous or asynchronous modes.
With IBM Spectrum Virtualize, Metro Mirror and Global Mirror are the IBM branded terms 
for the functions that are synchronous remote copy and asynchronous remote copy. 
Synchronous remote copy ensures that updates are committed at the primary and secondary 
volumes before the application considers the updates complete. Therefore, the secondary 
volume is fully up-to-date if it is needed in a failover.
However, the application is fully exposed to the latency and bandwidth limitations of the 
communication link to the secondary volume. In a truly remote situation, this extra latency can 
have a significant, adverse effect on application performance.
Special configuration guidelines exist for SAN fabrics and IP networks that are used for data 
replication. Consider the distance and available bandwidth of the intersite links when planning 
for synchronous remote copy.
A function of Global Mirror that is designed for low bandwidth was introduced in IBM 
Spectrum Virtualize. It uses change volumes that are associated with the primary and 
secondary volumes. These volumes are used to record changes to the remote copy volume, 
the FlashCopy relationship that exists between the secondary volume and the change 
volume, and between the primary volume and the change volume.