EMC Symmetrix

The Symmetrix system is EMC Corporation's enterprise storage array. It was the flagship product of EMC in the 1990s and 2000s.

Symmetrix arrays, EMC's flagship product at that time, began shipping in 1990 as a storage array connected to an IBM mainframe via the block multiplexer channel. Newer generations of Symmetrix brought additional host connection protocols which include ESCON, SCSI, Fibre Channel-based storage area networks (SANs), FICON and iSCSI. The Symmetrix product was initially popular within the airline industry and with companies that were willing to deviate from the safety of IBM's 3390 disk subsystem and take a risk with the unproven Symmetrix array. This product is the main reason for the rapid growth of EMC in the 1990s, both in size and value, from a company valued hundreds of millions of dollars to a multi-billion company.Moshe Yanai managed the Symmetrix development from the product's inception in 1987 until shortly before leaving EMC in 2001, and his Symmetrix development team grew from several people to thousands.

The Direct Matrix Architecture (DMX) product line with models DMX800, DMX1000 and DMX2000 were announced in February 2003.

The Symmetrix Remote Data Facility (SRDF) is a family of [ software products that facilitates the data replication from one Symmetrix storage array to another through a storage area network or (IP) network.

SRDF logically pairs a device or a group of devices from each array and replicates data from one to the other synchronously or asynchronously. An established pair of devices can be split, so that separate hosts can access the same data independently (maybe for backup), and then be resynchronised.

In synchronous mode (SRDF/S), the primary array waits until the secondary array has acknowledged each write before the next write is accepted, ensuring that the replicated copy of the data is always as current as the primary. However, the latency due to propagation increases significantly with distance.

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