Sanrad is shipping its Global Data Replication product, providing asynchronous and synchronous replication between similar or dissimilar drives in an IP SAN.

Fibre Channel SANs already have a replication product to provide disaster recovery (DR). If one SAN goes down the networked SAN with the replicated contents can be brought into play instead so that data access isn't lost. Disaster Recovery sites can be tens, hundreds or thousands of miles apart.

With synchronous replication data is written to the primary and DR SANs at the same time and a high-cost, high-speed network link is needed. Asynchronous replication queues data to the remote site across a slower speed and cheaper link. Slightly more data can be lost if the primary site goes down.

Often replication products require identical drive arrays to be used. It saves money if cheaper or dissimilar drive arrays can be used though. However the replication product has to be more capable. Sanrad IP SANs are virtualised though a V-Switch and thus decoupled from the underlying drive arrays. This makes replication between dissimilar arrays and disks easier. The company has added StoragePro software to the V-switch to take advantage of that to provide like-to-like and like-to-unlike array and drive replication across IP links.

A Sanrad GDR licence costs around $10,000 (£6,000)

As a comparison EMC Replication Manager/Local can be bought from Gateway for $26,400. EMC's Symmetrix SRDF replication product can cost tens of thousands of dollars more.

To save money on EMC replication products NationWide building society has just spent over a million dollars on a Kashya replication appliance. This way NationWide has avoided buying the four or five software products needed to replicate data between EMC Symmetrix arrays and cross-platform to EMC Clariion arrays.

The company has also cut four full-time replication employees to one.

A Sanrad IP SAN replication facility will cost less than one hundredth of the Kashya product. A white paper discussing global data replication can be found here.