Hu Yoshida

Global Storage Virtualization with GAD is GA!

Blog Post created by Hu Yoshida Employee on Nov 11, 2014

Aug 19, 2014


The global active device (GAD) feature that we announced with our VSP G1000 storage array on April 23 of this year has been released for General Availability after extensive testing of its use for both block and file storage by several key customer accounts.


GAD greatly simplifies and automates high availability to ensure continuous operations for your most mission critical data and applications. With GAD we are extending storage virtualization, which up to now has been vertically oriented behind our enterprise storage systems so that it is extended horizontally across multiple enterprise storage systems. We now have Global Storage Virtualization that integrates multiple virtualized storage platforms with active-active clustering and volumes that span physical systems. Global active devices are the spanned virtual volumes.


A virtual volume now spans physical storage systems that are separated by up to metro distances to provide continuous operations in the event that one of the storage systems or a server in a stretch server cluster should happen to fail. Operations continue without any interruption. GAD also provides workload mobility to balance the workload between servers or to take down a server for maintenance. Another benefit of GAD is to enable non-disruptive migration of data volumes between storage systems. GAD is implemented directly in the VSP G1000 through the Storage Virtualization Operating System (SVOS) that resides in each G1000. This avoids the complexity and limitations of appliances that are inserted in front of storage systems to perform similar functions.

We will be demonstrating GAD with VMware Stretch Clusters at VMworld in San Francisco, August 24 to 28. Please come by booth 905 and see how we provide “always available” VMware with Active/Active HA data centers.



In a similar way we can provide “always available” Microsoft Hyper-V.  GAD for back-end storage compliments Microsoft Multi-site Cluster / Stretch Cluster for Application Servers failover/failback workloads. Depending on requirements, server cross-site connections can eliminate the need for failover/failback on the server side.



HDS plans to do self-certification of Oracle compatibility later this year. Oracle administrators relate that host based mirroring can be complex to implement and operate.  It requires RAC nodes be cross-connected with ISL lines. It uses significant host based cycles which steal power from servers, and the design requires complex operations for failover and failback.  All of which must be executed perfectly.  GAD avoids all that, and in addition to its active-active design maximizing resource utilization, has added other cost-reducing aspects. Customers can reduce Oracle license costs with SVOS and GAD through a cascade of benefits: less host based replication = less host CPUs = less Oracle licenses.  Failover, failback, better than Active Data Guard – Avoid Active Data Guard licenses.



If you have high availability requirements please explore our GAD capabilities. You can link to this PDF, which describes SVOS and GAD at a high level, visit the global-active device product page on, or you can contact your HDS reseller for more information.