## 6.4.4 IP Compression 

IBM FS9100 can average the IP compression capability to speed up replication cycles or to reduce the bandwidth utilization. 

This feature reduces the volume of data that must be transmitted during remote copy operations by using compression capabilities similar to those experienced with existing Real-time Compression implementations. 

No License:  IP compression feature does not require an RtC software license. 

The data compression is made within the IP replication component of the IBM Spectrum Virtualize code. It can be used with all the remote copy technology (Metro Mirror, Global Mirror, and Global Mirror Change Volume). The IP compression is supported, with some restrictions, in the following systems: 

GLYPH<SM590000> SAN Volume controller with CF8 nodes 

GLYPH<SM590000> SAN Volume controller with CG8 nodes 

GLYPH<SM590000> SAN Volume controller with DH8 nodes 

GLYPH<SM590000> SAN Volume controller with SV1nodes 

GLYPH<SM590000> FlashSystem V9000 

GLYPH<SM590000> Storwize V7000 Gen1 

GLYPH<SM590000> Storwize V7000 Gen2, Gen2+, Gen3 

GLYPH<SM590000> Storwize V5000 Gen2 

GLYPH<SM590000> Storwize V5100, V5000E 

GLYPH<SM590000> FlashSystem 9100 

The IP compression can be enabled on hardware configurations that support RtC only. The IP compression feature provides two kinds of compression mechanisms: The hardware compression and software compression. The hardware compression is active when compression accelerator cards are available, otherwise software compression is used. 

Hardware compression makes use of currently underused cards. The internal resources are shared between RACE and IP compression. Software compression uses the system CPU and might have an impact on heavily used systems. 

To evaluate the benefits of the IP compression, the Comprestimator tool can be used to estimate the compression ratio of the data to be replicated. The IP compression can be enabled and disabled without stopping the remote copy relationship by using the mkippartnership  and chpartnership  commands with the -compress  parameter. Furthermore, in systems with replication enabled in both directions, the IP compression can be enabled in only one direction. IP compression is supported for IPv4 and IPv6 partnerships. 

