One company with a good vantage point of the merits of Dynamic Random Access Memory (DRAM) solid-state drive (SSD) and NAND flash is CCP hf, a Reykjavik, Iceland-based online game producer that uses both technologies.
CCP began using DRAM SSD technology from Texas Memory Systems Inc. nearly five years ago when it noticed its core product, Eve Online, showing signs of in-game lag due to the increasing stress put on some areas of its database and storage array.
The IT group now reserves its DRAM SSD-based RamSan-400 for the part of the database that's accessed the most and uses its newer "cached flash" RamSan-500 -- which has 64 GB of DRAM cache and 2 TB of RAID-protected single-level cell (SLC) NAND flash -- for the bulk of the database calls. It credits solid-state drives with helping the system to handle 53,850 simultaneous users in mid-May.
"Over time, we have progressively moved away from Fibre Channel hard disk drive (HDD) storage, as the I/O performance just does not keep up with our demands," IT Director Jon-Carlos Mayes wrote in an email. "To put it simply, for a database like ours, there is just no comparison."
Mayes described the DRAM SSD system's performance as "blindingly fast I/O" for both reads and writes, but at the expense of overall storage capacity. The 2 TB SLC flash-based RamSan-500 handles capacity needs and also provides "very fast read performance," Mayes wrote.
The DRAM solid-state drive-based RamSan-400 system claims to be able to attain 400,000 IOPS, for both reads and writes. Although CCP hasn't verified that number through testing, it appeared fairly accurate based on database usage and percentage usage of the RamSan device, according to Mayes. The RamSan-500, which has both DRAM and NAND flash technology, claims read performance of 100,000 IOPS and write performance of 25,000 IOPS, according to Texas Memory Systems.
CCP is also testing a flash-only RamSan-20, which has 450 GB of SLC NAND flash storage attached via PCI Express. The RamSan-20 claims to handle 120,000 read IOPS vs. 50,000 write IOPS, illustrating the difference in performance for reads/write that users might expect to see in a dedicated SLC-based flash system.
For systems produced by Texas Memory Systems, the list price of DRAM SSD is $300 per gigabyte, while SLC-based flash SSD is $40 to $70 per gigabyte, according to Woody Hutsell, the company's president.
The 2 TB Flash-based RamSan-500, which has 32 GB of DRAM cache, lists at $150,000, whereas pricing for the all-Flash 5 TB RamSan-620 is $220,000, Hutsell said. The latest DRAM SSD-based 512 GB RamSan-440 lists at $180,000. Today's list price for the RamSan-400 is $61,000, while the RamSan-20 is $18,000.