POWER8 CAPI Flash: In-memory expansion to speed data access
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If you missed my post last week on the IBM POWER8 Coherent Accelerator Processor Interface, or CAPI, you might want to read that first.
CAPI can also be leveraged as the basis for flash in-memory expansion. An innovative solution designed to reduce latency and speed up access to data, CAPI Flash creates a bigger memory store, which as we know, is the driving force behind fast access to data.
While CAPI is designed to speed up workloads, CAPI Flash serves to significantly lower operational and deployment costs by creating a faster path to a larger store of memory. As such, CAPI Flash manages to reduce the number of servers required to accomplish the same workloads.
The elimination of I/O overhead, which is inherent to the CAPI, also factors in as an essential benefit of CAPI Flash. With CAPI Flash, the number of instructions required to retrieve data is reduced from 20,000 to fewer than 500.
The IBM Data Engine for NoSQL uses CAPI Flash and software from Redis Labs to reduce operational costs by cutting through complexities and creating an entirely new level of efficiency for NoSQL in-memory databases running key value store (KVS) workloads: most in-memory databases consist of a vast network of costly compute nodes. Since there’s only so much data that can be stored on a node, more data requires nodes, fueling a steady rise in cost and complexity.
OpenPOWER partner Redis Labs and IBM have partnered on the Data Engine for NoSQL's implementation of CAPI Flash, which attaches flash arrays that put 40 TB of memory onto the POWER CPU – resulting in a level of acceleration that exceeds that of a fast hard drive. The impact on cost, speed, efficiency, and latency is significant. Key among the metrics:
Concerning the reduction in nodes – which represents just one angle of the level complexity that CAPI Flash manages to eliminate – imagine the difference between juggling 24 balls versus one that has all of the same functionality. That’s CAPI Flash.
Moving forward, possibly the most significant benefit of CAPI Flash is a concept known as “eventual coherence.”
A key challenge in almost all NoSQL environments is that when data is written to a node that is networked within a database, the data is not instantly available. The new data will not appear on the system until coherency is achieved among all of the nodes. If a node fails before it is replicated throughout the system, the data will be lost.
With CAPI Flash, data appears and is accessible on the system as it is entered. Even if a node fails, the data will remain on the flash.
One final point worth mentioning: while most conversations about CAPI Flash to date have focused on NoSQL, the work that we are doing is applicable to any application that has a large memory footprint.
Learn more about CAPI, and other unique advantages offered by Power Systems scale-out servers, in this paper written by Robert Frances Group, "Th
For more information on the IBM Data Engine for NoSQL, read the solution brief.