STEC's ZeusIOPS SSD is the market leader for array-based SSD through its OEM deals with EMC Corp., IBM, Hitachi Data Systems (HDS) and other vendors. STEC product manager Swapna Yasarapu said the ZeusRAM SSD is aimed at NAS and unified storage systems as well as data deduplication backup appliances rather than inside storage arrays.
The main difference between the ZeusRAM and ZeusIOPS SSD is that ZeusRAM uses DRAM for primary data storage while ZeusIOPS uses flash memory. The ZeusRAM is designed for persistent writes. STEC claims it can deliver a sustained performance of up to 130,000 read IOPS and 88,000 write IOPS compared to 80,000 read and 45,000 write IOPS for the ZeusIOPS.
ZeusRAM is a 3.5-inch 6 Gbps SAS device with 8 GB of capacity. STEC claims its wear-resistant design for write intensive workloads works best on high-write transactional-oriented applications that require fast write performance. Yasarapu said its new SSD provides latency of less than 23 microseconds for file systems.
"This goes into appliances with file systems or operating systems," she said. "Any appliance running on the network can use this [SSD] so the file system or operating system can speed up application responses."
Analyst Jim Handy of Objective Analysis said the fast write-commit feature makes ZeusRAM a good fit for online transaction processing (OLT) applications.
"The fast write commit feature is one that should be of significant interest to the on-line transaction processing (OLTP) community since high-security coding depends upon verifying that a write has been acted upon by persistent storage," he said.
IDC research manager for solid state drives Jeff Janukowicz said ZeusRAM's use of super capacitors instead of batteries to hold its flash RAM instead of batteries makes it easier to recover from loss of power.
"While DRAM-based SSDs have been around for some time, they have been a niche product in part due to high cost and use of batteries to create a nonvolatile storage device," he said. "ZeusRAM does not leverage a battery, instead it used STEC's super capacitor technology with NAND memory to create a nonvolatile storage device."
Yasarapu said OEM partners are sampling ZeusRAM SSDs.
Violin adds multi-level cell SSD
The Violin 3140 Capacity Flash Memory Array is a 3U high capacity MLC device that holds from 10 TB to 40 TB of flash, and Violin claims the device scales to 500 TB with more than 2 million IOPS in a rack. The 3140 costs $650,000 for 40 TB – which comes to about $16 per gigabyte.
The 3140 is a higher capacity alternative to the Violin 3200 single-level cell (SLC) that began shipping in May. The 3200 is the better performer but only scales to 10 TB.
Violin CEO Don Basile said the latency for the 3140 is above 400 microseconds, compared to 100 microseconds to the more expensive 3200. "That's not a huge difference, but it could make folks looking for high performance go one way or another," he said. "This  is for customers who want more density. They may not need more than 20,000 random I/O per server but they need more capacity."
Violin sells its flash appliance as an alternative to using SSDs in storage arrays. The Violin appliances work alongside SAN arrays to increase performance. Basile said now that Violin has delivered a capacity improvement over the 3200, Violin's next product will improve performance.
"Violin is going after CIOs who want to put their entire database into solid state storage," Handy said. "It's a more expensive solution than managing data into and out of a smaller SSD, but it's more sure-fire than tiering -- which can introduce occasional timing ambiguities --and Violin's solution is much less costly than an all-DRAM approach."
While MLC devices a year ago were not considered good enough for the enterprise from a performance standpoint, flash vendors have worked to increase MLC performance without losing its price advantage over SLC.
"Vendors, like Violin, have made significant advancements over the last year that make leveraging MLC in the enterprise a realistic option," Janukowicz said. "Today, MLC can provide the performance and endurance required for many applications.
Basile said he expects about 10% to 30% of applications running with SSDs will use SLC arrays with the rest running on cheaper MLC. "Where you want the most I/Os per unit space for latency-sensitive applications, you'll use SLC," he said. "MLC has an excellent performance compared to disk arrays, with better space and power utilization."