With 5,000 employees and 280 branch offices, Associated Bank is a prime example of a medium-sized business with big data demands.
After acquiring another bank in 2006, its SAN grew from 17TB to 300TB in less than a year. Since then, due to more applications coming online and federal regulations requiring more data retention, the SAN has grown to 900TB, or 52 times its original size.
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Dan Marbes, a systems engineer at the Green Bay, Wisc.-based bank, decided to try SSDs (solid-state drives) to increase the performance on I/O-hungry applications, while reducing his spindle footprint.
He bought three SSDs to serve as top-tier storage for BI applications on his SAN. The flash storage outperformed 60 15,000-rpm Fibre Channel disk drives when it came to small-block reads.
However, when Marbes used the SSDs for large-block random reads and any writes, "The 60 15K spindles crushed the SSDs," he said, demonstrating that flash deployments should be strategically targeted at specific applications.
SSDs use non-volatile NAND flash memory chips, which are cheaper than DRAM chips but are still as much as 18 times more expensive than 15,000-rpm Fibre Channel or serial SCSI (SAS) drives, according to Gregory Wong, an analyst with market research firm Forward Insights. But prices continue to fall, mostly due to consumer adoption of solid-state drive and NAND flash card technology, which ultimately affects the cost of data center-class products.
According to the market research firm IDC, the global outlook for client-side SSDs -- those used in consumer products such as laptops and tablets -- is expected to grow 10-fold, from 11 million units in 2011 to 100 million units in 2015. The use of NAND in 256GB SSDs is forecast to more than double from 19 percent of all NAND used in SSDs in 2011 to 42 percent in 2015. Further, demand for 512GB SSDs is expected to grow from a 0.3 percent portion in 2011 to 8 percent in 2015, also underscoring the growing interest in higher-density SSDs.
Wong expects mass adoption of SSDs by consumers won't occur until the price has reached about $1 per gigabyte, sometime in the second half of 2012. The more consumer NAND flash that is purchased, the lower the overall price of flash products, even in the data center.
Currently, the price for NAND flash in a SSD form factor is about $9 per gigabyte for high-end, single-level cell (SLC) flash and $3 per gigabyte or multilevel cell (MLC) flash. A new class of MLC, called enterprise MLC or eMLC, can withstand up to 30 times more writes over consumer-grade MLC flash, but it also comes with a price premium of about 20 percent, Wong said.
By comparison, a Fibre Channel or SAS drive costs between 50 and 60 cents per gigabyte.
Many array manufacturers, such as EMC and Hitachi Data Systems, offer an SSD option, which is ability to fill array drive slots with SSDs in 2.5- or 3.5-inch hard drive form factors. Some vendors also offer automated tiering software that migrates the most frequently accessed data to the SSDs, while keeping less critical data on lower-cost hard drives.