Pure compression floats its gate array

Pure Storage has built a compressing FPGA to speed deep data reduction in its FlashArrays and so increase their effective capacity.

An FPGA (field programmable gate array) is a semiconductor device built from logic blocks and designed to carry out a set of functions. It is programmed to focus on a particular function, such as compression, and carry it out faster than having the same function performed by software running in a general-purpose CPU. Pure Storage’s all-flash FlashArray storage products use data compression to increase the effective capacity of the array with the idea being they’ll lower the total cost of ownership.

Dan Kogan, VP for FlashArray product management at Pure, said in a briefing that there is a 2-stage compression process: an initial inline run when data is first loaded into the array and before it is written to the flash media, followed by a background deep compression run when the array controllers have idle capacity.

The deep compression routine is run post-data ingress so as not to slow the array controller CPUs down with the deep compression compute load.

Pure DCA compressing FPGA card

By instituting an inline compressing FPGA, called a DCA card, Pure can relieve the array controller processors of the deep compression workload and provide deep compression when data is first  loaded with no data ingress rate slowdown. Kogan said that the DCA card improves the inline step of the compression by 30 percent.

Pure’s compression algorithms use variable block sizes with machine learning techniques based on customer data. They auto-detect the data type and use specific routines tailored to the data type. 

There will still be a 2-stage compression process, with the initial inline run using the FPGA and a second deeper compression run reducing the data still further when the array controllers have the opportunity to do so.

Pure Storage compression stage diagram before the DCA FPGA and using the FPGA.

The FlashArray//XL will get the new DCA FPGA and customers will not be charged extra for the feature. There is no upgrade capability for existing arrays; this needs to be a green field deployment and all new data that is written is compressed, and then decompressed when read.

All shipping FlashArray//XL systems will be fitted with the new compressing FPGA. The technology may be extensible to Pure’s FlashBlade systems but there are no plans to do this.