Additional Storage Performance Efficiencies for Mainframes
by Hu Yoshida on Feb 21, 2012
UPDATE: Since this post was first published, I was challenged on a performance chart that I showed. Since I did not have the details, I took this post down until I could verify the test parameters with the owner of the performance chart. Unfortunately, the owner would not release these details so I left the post down, I should have edited it and acknowledged my error. I have asked marketing to remove the chart from all other marketing materials. In the meantime, if a customer would like to see a third party comparison, they can contact Pat Artis of Performance Associates: http://www.perfassoc.com/. Since Performance Associates owns the results customers will have to pay for their reports.
Since my last post on Storage Performance Efficiency, Claus wrote on the use of HDP, Hitachi Dynamic Provisioning and HDT, Hitachi Dynamic Tiering for mainframes on Virtual Storage Platform (VSP). Naturally, this prompted me to think of the specific performance efficiency implications for mainframes.
HDP brings the performance benefits of automated wide striping and HDT automatically keeps the hot pages of data on the highest performance tier of storage for mainframes, just as it does for open systems. There are differences between open systems and mainframe implementation due to mainframe CKD and CCHHR formats—for instance, the page size is optimized for mainframe storage formats and storage reclamation must be host initiate.
There are also additional performance efficiencies specific for mainframes.
Mainframe HDP is the foundation for Extended Addressable Volumes, which increases the size of 3390 volumes from 65,520 cylinders to 262,668 cylinders. This, along with HyperPAV—which facilitates multiple accesses to a volume—enhances throughput with many more concurrent I/O operations.
The thin provisioning of HDP also increases the performance of mainframe functions that move, copy, or replicate these thin volumes like Concurrent Copy, FlashCopy V02, and HUR, since the actual volumes are smaller.
If you have mainframes, check out the capacity and performance efficiency of VSP with HDP and HDT.
For other posts on maximizing storage and capacity efficiencies, check these out: