On-Demand, High-Performance Storage for the Hybrid Cloud Era
Mainframe organizations have long struggled with the rigidity of traditional storage models. Buying and provisioning new DASD often meant long procurement cycles, high costs, and vendor lock-in. Zaac, VirtualZ Computing’s patented storage solution, changes that equation by delivering on-demand, no-code mainframe storage that connects seamlessly to cloud object storage, iSCSI, and NFS environments.
With our iSCSI support, Zaac gives mainframe customers even more flexibility — providing high-performance, on-premises storage options that complement or even replace cloud storage when speed, security, or locality matter most.
Why iSCSI Matters for Mainframe Customers
Cloud storage (Amazon S3, Azure Blob, Google Cloud Storage, Glacier, etc.) provides enormous cost benefits and scalability. But cloud isn’t always the right fit:
- Some applications require lower latency than cloud roundtrips can deliver.
- Certain industries resist placing their crown jewels of data in the public cloud.
- Bandwidth limitations can make remote storage impractical.
That’s where iSCSI comes in. With Zaac, mainframe teams can:
- Leverage existing enterprise storage investments across Windows, Linux, and VMware environments.
- Deploy on-premises SAN or iSCSI appliances for near-native mainframe disk performance.
- Control data locality while still enjoying Zaac’s agility and cost benefits.
For example, an iSCSI device connected to the same datacenter network as the mainframe can deliver speeds close to native DASD — without the complexity or expense of traditional mainframe storage.
Agility + Cost Efficiency
Zaac with iSCSI support allows storage to scale up or down on demand. Need 50TB for a project? Provision it instantly. No need to “call someone” or wait weeks for hardware — storage is available as quickly as a screen refresh.
And the economics are compelling:
- Enterprise-grade iSCSI devices can deliver hundreds of terabytes of storage for under $10,000.
- Zaac ensures these devices behave just like standard mainframe DASD, supporting DB2, VSAM, and even low-level EXCP workloads — without code changes.
This means organizations can offload non-mission-critical data to lower-cost iSCSI storage while reserving premium storage for workloads that demand it — saving pennies on the dollar compared to traditional DASD.
Enterprise-Grade Reliability
Zaac is engineered with advanced caching and journaling features that maintain reliability and performance:
- System Logger integration ensures no data is lost, even during network interruptions.
- Duplexing across multiple providers allows replication between iSCSI on-prem storage, AWS, Azure, and Google Cloud simultaneously.
- Virtual Disk + Virtual Tape support in a single product lets organizations simplify both disk and tape strategies with one solution.
Open Architecture, Patented Technology
What sets Zaac apart is its ability to transform unique mainframe I/O patterns into industry-standard protocols like iSCSI, NFS, and S3. This patented approach provides an open-ended architecture, enabling future support for any storage platform customers choose — even Dropbox or other niche providers — without mainframe changes.
Unlike competitors that emulate tape-only devices, Zaac provides true virtual disk emulation. Any application that runs against a physical DASD can run unchanged against a Zaac-provisioned disk, regardless of whether it’s backed by iSCSI, NFS, or cloud object storage.
Adoption Is Simple
Deploying Zaac is straightforward:
- Install the software package on z/OS.
- Configure iSCSI targets (or cloud/NFS) and provide credentials.
- Provision virtual disks or tapes through Zaac utilities.
- Bring them online with standard operator commands — z/OS applications see them as ordinary DASD.
In most cases, a seasoned storage administrator can be up and running in just a couple of hours.
A New Storage Era for the Mainframe
With iSCSI support, Zaac now gives mainframe organizations the full spectrum of storage choices:
- Cloud Object Storage (S3, Glacier, etc.) for low-cost archival and massive scalability.
- iSCSI for high-performance, on-prem storage and data locality.
- NFS for file-based interoperability.
This flexibility eliminates vendor lock-in, lowers costs, and brings mainframe storage into alignment with the way every other enterprise platform has operated for decades — scalable, agile, and cost-effective.
Zaac makes it possible for mainframe customers to finally manage storage the way they want: on demand, across any platform, at a fraction of the cost.
Next Steps
- Schedule a briefing.
- Watch a demo of Zaac.
- Try Zaac.
Learn More
- Visit our Customer Briefing Center.
- Review all VirtualZ Use Cases, Thought Leadership papers, and Solution Briefs.
- Explore our YouTube channel, podcasts, and blog.
- Still have questions? Contact us.




