IBM Support

Info Letter: Tape attached TS7740 (3957-V07), TS7720-T (3957-VEB) and TS7760-T (3957-VEC) code update considerations for R4.2 GA (8.42.0.71) or higher

News


Abstract

The R4.2 GA (8.42.0.71) release of TS7700 microcode may exhibit reduced DD peak write performance with Single Active Deferred Copy mode on tape attached systems when utilizing LZ4 or ZSTD compression.

Content

Affected hardware configurations

  • TS7740 - Only those in a grid configuration, operating in DD write Single Active Deferred Copy mode, when using LZ4 or ZSTD compression
  • TS7720 Tape Attached - Only those in a grid configuration, operating in DD write Single Active Deferred Copy mode, when using LZ4 or ZSTD compression
  • TS7760 Tape Attached - Only those in a grid configuration, operating in DD write Single Active Deferred Copy mode, when using LZ4 or ZSTD compression

 

Explanation of potential performance impact
Peak copy rate of R4.2 GA (8.42.0.71), when processing DD write Single Active Deferred copies, using LZ4 or ZSTD compression, may be reduced up to 8% compared to prior R4.1 Phase 2 (8.41.200.113) level of code.

Note: For additional details concerning TS7700 performance, check out the available whitepaper (here R4.1 Phase 2):
            http://www-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/WP102751
            The references to “D” stand for deferred copy mode. DD represents deferred copies for cluster 0, and deferred copies for cluster 1, so deferred copies for both clusters.   

 

[{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"STFS69","label":"TS7700"},"Component":"","Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"All Versions","Edition":"","Line of Business":{"code":"LOB26","label":"Storage"}}]

Document Information

Modified date:
21 September 2018

UID

ibm10732663