Monday, May 19, 2014

DS8870 announcement - Flash optimization II

This is an announcement from last week : 'IBM DS8870 next-generation flash systems deliver high availability and better performance for critical environments (ZG14-0119)'. However last week I was at the IBM Technical University for System z in Budapest and I wanted to have a closer look at the announcement before writing about it. And, by sheer coincidence, this is the first time in my life that I actually saw the real machine before I even read the announcement as we visited the DS8000 plant while in Hungary.

IBM fulfills an earlier statement of direction about the use of a "new high-density flash storage module for selected IBM disk systems, including the IBM System Storage DS8000". Now you might say : didn't they already announce an all flash box last year. Well, yes and no. They announced an all SSD box. Now you may argue again : isn't SSD the same as flash. Well, yes and no. It's more or less the same type of disks, or let's say, flash cards. Let's make a little detour to get a better understanding of this.
IBM has its FlashSystem 840 for open systems which comes from a recent acquisition of Texas Memory Systems. It aims purely at performance and promises extremely high performance and extremely low latency. How does it reach that : well, by concentrating solely on getting the data as fast as possible without any software functionality or storage controller in between that does e.g. compression, deduplication . . . And that's, to me at least, the main distinction between what IBM calls Flash and SSD. As a result the announcement says "it will help to increase IOPS by up to 4 times as compared to SSDs and up to 30 times as compared to spinning drives".

This is realized with new High Performance Flash Enclosures (HPFEs). This "high-performance flash enclosure is directly attached to the PCIe fabric, enabling increased bandwidth and transaction processing capability. The 1U enclosure contains a pair of powerful redundant RAID controllers".

Here's a configuration with just HPFEs in the box.

To the left side, you can see that 4 HPFEs fill the empty slot that was intentionally there from the beginning of the DS8870. ("Intentionally left blank" you might say). One enclosure contains 30 1.8'' flash drives of 400GB giving you a raw capacity of 12TB. If you only use the upper left slot for HPFEs, they can be combined with other types of disks in the regular disk slots.

The box you see here is an "all-flash, single rack system configured with only flash and up to 96 TB of capacity (73.6 TB of usable capacity) in a 8U of space". This all flash box also "provides twice as many I/O enclosures and up to twice as many host adapters as the standard DS8870 single frame configuration" See the extra host adapters in the green square.

Let me also give you a brief summary of the other functionalities that were announced :
General availability : June 6, 2014. Some field availability is only in September.

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