EMC is now shipping its long-awaited entry in the server-based flash storage market while laying the groundwork for a future appliance based on the same technology.
The company is positioning VFCache, previously code-named Project Lightning, as an extension of its FAST (Fully Automated Storage Tiering) architecture. That system is designed to shift data among various types of systems to keep the most-needed data most available to applications. VFCache forms another tier of storage within a server, accessible via the system's fast PCIe bus.
Other vendors beat EMC to this approach, most famously Fusion-io, which has been selling PCIe-based flash cards since 2008. But EMC says VFCache can take this approach to storage into the mainstream, beyond specialized companies such as Apple and Facebook. It will tie into EMC storage arrays already in use in traditional enterprises and provide those users a dramatic boost in performance, according to the company.
After speeding up storage access by bringing intensively used data into servers, EMC plans to boost performance even more by combining multiple PCIe cards in an appliance, code-named Thunder. Multiple servers will be able to connect to a shared Thunder via InfiniBand or 40-Gigabit Ethernet, said Mark Sorenson, senior vice president and general manager of EMC's flash business unit.
While spinning hard disk drives (HDDs) have steadily grown in capacity over the past several years, getting to the data they hold has not gotten faster. Flash overcomes that speed limitation, and EMC has offered flash since 2008 in the form of SSDs (solid-state drives) for its storage arrays. PCIe flash cards in servers add to flash's speed advantage by eliminating the SAN (storage-area network) connections that data from those SSDs needs to traverse.
EMC claims that while SSDs in a storage array deliver 300 times faster data access than HDDs, PCIe flash cards offer 4,000 times faster access than HDDs. That gain comes from both higher I/O performance and lower latency. The Thunder appliance will be able to deliver similar latency and even higher I/O performance because it will be able to use several PCIe buses in parallel, Sorenson said.
VFCache will start out as a 300GB PCIe flash card, with larger sizes coming later. It can be used in all standard rack-mounted servers and will come in a different form factor for blade servers in the future. The Thunder appliance could be configured with 10TB to 15TB of flash capacity, Sorenson said.
VFCache will act as a "read" cache of the data most immediately needed, a copy of which will also remain in persistent storage. In future versions, it will get tighter integration with FAST, including the ability to give hints about what data it may use next. Sorenson said. The product will also gain a deduplication feature for more efficient use of its storage space
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