Impact of z14 on Processor Cache and MLC Expenses

Todd Havekost

By Todd Havekost

Expense reduction initiatives among IT organizations typically prioritize efforts to reduce IBM Monthly License Charge (MLC) software expense, which commonly represents the single largest line item in the mainframe budget.

On current (z13 and z14) mainframe processors, at least one-third and often more than one-half of all machine cycles are spent waiting for instructions and data to be staged into level one processor cache so that they can be executed. Since such a significant portion of CPU consumption is dependent on processor cache efficiency, awareness of your key cache metrics and the actions you can take to improve cache efficiency are both essential.

This is the final article in a four-part series focusing on this vital but often overlooked subject area. (You can read Article 1, Article 2, and Article 3.) This article examines the changes in processor cache design for the z14 processor model. The z14 reflects evolutionary changes in processor cache from the z13 in contrast to the revolutionary changes that occurred between the zEC12 and z13. The cache design changes for the z14 were particularly designed to help workloads that place high demands on processor cache. These “high RNI” workloads frequently experienced a negative impact when migrating from the zEC12 to z13.

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How Much Flash Do I Need Part 2: Proving the Configuration

By Jim Sedgwick

Before making a costly Flash purchase, it’s always a good idea to use some science to forecast if the new storage hardware configuration, and especially the costly Flash you purchase, is going to be able to handle your workload. Is your planned purchase performance capacity actually too much, so that you aren’t getting your money’s worth? Or, even worse, is your planned hardware purchase too little?

In Part 1 of this blog, we discovered that our customer just might be planning to purchase more Flash capacity than their unique workload requires. In part 2 we will demonstrate how we were able to use modeling techniques to further understand how the proposed new storage configuration will handle their current workload. We will also project how this workload will affect response times when the workload increases into the future, as workloads tend to do.

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The Circle of (Storage) Life

Storage Life Cycle

Lee LaFreseBy Lee LaFrese

Remember the Lion King? Simba starts off as a little cub, and his father, Mufasa, is king. Over time, Simba goes through a lot of growing pains but eventually matures to take over his father’s role despite the best efforts of his Uncle Scar to prevent it. This is the circle of life. It kind of reminds me of the storage life cycle only without the Elton John score!

Hardware Will Eventually Fail and Software Will Eventually Work

New storage technologies are quickly maturing and replacing legacy platforms. But will they be mature enough to meet your high availability, high performance IT infrastructure needs?

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