Limitations caused by the speed of light typically cause applications to time out when data is being replicated between machines over distance. This means that if a machine sending data does not receive confirmation from the recipient machine within a certain span of time, it considers the computer operation failed.
Typically, vendors have solved this problem by sending data asynchronously over distances, so that a response message is not required from the recipient machine. Asynchronous data replication, however, means that if a disaster occurs, causing a primary data center to go down, the data in transit to the secondary data center is lost. In order to share data in real-time, synchronous replication is required.
EMC's Vplex appliance basically cheats speed of light limitations by sending across a light-weight code with the data to invalidate the requirement for a fast response between servers in multiple sites -- something EMC calls "cache coherency."
The appliance rests between the storage network switches and the storage array.
Gallagher said the Vplex appliances can scale from two to eight nodes or locations. When it comes to clustered applications, such as Oracle RAC or VMware HA, however, replication distances are limited to 100 kilometers, he said.
In addition to the new functionality, EMC also reduced the size of the appliance by using smaller rack-mounted boxes with more powerful Intel multi-core processors, PCI Gen 2 cards for faster throughput, and new 10-Gigabit Ethernet WAN interfaces for faster communications between clusters.
EMC is charging $100,000 for an appliance with 1TB of capacity on it, but Gallagher said street prices would vary depending on the size of the implementation.
In related news, EMC also announced has added support for native Fibre Channel over Ethernet (FCoE) connectivity on its high-end Symmetrix Vmax array.
EMC competitor NetApp added FCoE capability to its high-end Fabric-Attached Storage (FAS) arrays last year through an upgrade in its Data ONTAP 8 operating system. Around the same time, EMC also added FCoE to its midrange line of VNX SAN/NAS arrays.
EMC said it was important to add the technology to address the trend toward the convergence of data networks in corporations today.
Additionally, EMC said it increased security on its Symmetrix Vmax with new support for external servers using RSA Data Protection Manager, which encrypts data at rest and stores and manages the encryption keys.
Lucas Mearian covers storage, disaster recovery and business continuity, financial services infrastructure and health care IT for Computerworld. Follow Lucas on Twitter at @lucasmearian or subscribe to Lucas's RSS feed. His email address is email@example.com.
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