8456ch_CopyServices.fm Draft Document for Review January 13, 2020 5:02 pm 5.3.4 Global Mirror 138  IBM DS8900F Architecture and Implementation GLYPH<SM590000> Support for almost unlimited distances between the local and remote sites, with the  distance typically limited only by the capabilities of the network and the channel extension  technology. You can use this unlimited distance to choose your remote site location based  on business needs. This capability enables site separation to add protection from  globalized disasters.  GLYPH<SM590000> A consistent and restartable copy of the data at the remote site, which is created with  minimal impact to applications at the local site.  GLYPH<SM590000> Data currency where, for many environments, the remote site lags behind the local site  typically 3 - 5 seconds, which minimizes the amount of data exposure if an unplanned  outage occurs. The actual lag in data currency that you experience depends on many  factors, including specific workload characteristics and bandwidth between the local and  remote sites.  GLYPH<SM590000> Dynamic selection of the Recovery Point Objective (RPO) that you want, based on  business requirements and optimization of available bandwidth.  GLYPH<SM590000> Session support in which data consistency at the remote site is internally managed across  up to eight storage units that are at the local site and the remote site.  GLYPH<SM590000> Efficient synchronization of the local and remote sites with support for failover and failback  operations. This configuration helps to reduce the time that is required to switch back to  the local site after a planned or unplanned outage. Global Mirror features the following benefits: Global Mirror performs automatic space releases on such space-efficient Journal targets.  This process will not occur on every consistency group formation, but often and in a regular  manner. The Global Mirror Journal volumes are a key use case for ESE to reduce the additional space  that is required for this configuration. You need extra storage at the remote site for these FlashCopies. However, you can define  your FlashCopy targets as Extent Space Efficient ESE volumes in an extent pool using small  extents.  Global Mirror is a two-site, long distance, asynchronous, remote copy technology. This  solution integrates the Global Copy and FlashCopy technologies. With Global Mirror, the data  that the host writes at the local site is asynchronously mirrored to the storage unit at the  remote site. With special management steps (under control of the local master storage unit),  a consistent copy of the data is automatically maintained and periodically updated by using  FlashCopy on the storage unit at the remote site. 