HDISV service description
Quick reference
- Overview
- What is HDISV?
- Key benefits
- Deployment modes
- CPU and memory sizes
- IBM z/OS Standard Image
- Storage
- Network and connectivity
- Important considerations
Overview
The IBM z/OS hosted on demand program for ISVs (HDISV) provides on-demand z/OS development and test environments for Independent Software Vendors (ISVs). Built on IBM Z hardware, HDISV delivers high-performance z/OS instances for software development, testing, and integration.
What is HDISV?
HDISV is a private, remote access z/OS environment designed specifically for ISV development needs. HDISV provides:
- Complete z/OS environment - Fully functional z/OS with development tools and provides traditional 3270 terminal access
- Multiple sizing options - Choose from Small, Medium, or Large configurations
- User storage - User data volumes up to 1 TB
- Secure access - VPN-protected connectivity to your instance
- Modern tooling - Includes the server side of IDz EE with RSE API to support Zowe Explorer and VSCode
Key benefits
1. On-demand flexibility
- Provision z/OS environments on-demand
- Flat monthly rate with no per-CPU cycle usage charges
2. Modern development experience
- IBM z/OS Standard Image provided by IBM with latest maintenance applied
- Includes essential development tools
- Easy to use with modern IDEs (VS Code, Eclipse)
- Ideal for CI/CD pipeline integration
3. High performance
- Runs on real IBM Z hardware
- Faster than x86-based emulation
- Quick startup times
Deployment modes
HDISV provides two deployment options for users to choose from:
- Managed Service - Ready-to-use z/OS environment appropriate for a wide range of dev/test use cases
- Linux Layer Access - Provides full DevMap control for more complex setups and additional resources not available in Managed Service; allows import of existing environments for simpler migration between systems
Managed Service mode
Managed Service mode provides a ready-to-use z/OS environment appropriate for a wide range of dev/test use cases.
Key features:
- Ready-to-use z/OS with SSH and 3270 access
- Turnkey z/OS maintenance
- User data preservation during recreate operations
- Simple lifecycle management
Ideal for:
- Teams with limited system administration capacity/expertise
- CI/CD pipeline integration
- Training on z/OS application development within your organization
Access methods:
- SSH to z/OS (as
zosadmnuser) - 3270 terminal emulator (port 2023)
- TSO/ISPF for interactive work
- RSI API to support Zowe Explorer and IDz EE Vscode and eclipse IDEs
- z/OSMF APIs
IBM performs all maintenance for z/OS and middleware. Maintenance can be applied on-demand using the "recreate" function. User data persists when the instance is recreated from the latest software image.
Linux Layer Access mode
For ISVs who have more system administration capacity/expertise and who require more complex setups, Linux Layer Access mode provides full DevMap control to access additional resources not available in Managed Service mode. Linux Layer Access also allows import of existing environments for simpler migration to HDISV from legacy systems.
What you get:
- SSH access to Linux layer
- Full control over the environment
- Ability to bring your own z/OS volumes
- Root access for customization
- Complete flexibility for complex development
Ideal for:
- Experienced ISV developers with system admin experience
- Complex development requiring system-level access
- Debugging system-level issues
- Custom z/OS configurations
- Training on system administration within your organization
- Research and experimentation
Access methods:
- SSH to Linux (as
cloud-useruser) - Root access in Linux via sudo
- Direct Linux file system access
- All other z/OS access methods
What is supported:
- Infrastructure provisioning
- Network connectivity
- Storage allocation
Users are responsible for managing all operating systems and software in Linux Layer Access mode.
Other Limitations:
- Instances cannot be recreated in Linux Layer Access mode - must terminate and create new instance
- No user data preservation on termination
- Requires system administration expertise
Mode switching
- Switching between Managed Service and Linux Layer Access requires terminating and creating a new instance
- No data is preserved when switching modes
- Plan carefully before switching modes
- Consider requirements when choosing mode
- May want to acquire a new Linux Layer environment and move data to it before terminating the existing environment
See Deployment Modes and Access Methods for detailed comparison of Managed Service and Linux Layer Access.
Comparison table
| Feature | Managed Service | Linux Layer Access |
|---|---|---|
| z/OS SSH access | Yes | Yes - if using Standard Image or configured in custom image |
| 3270 terminal | Yes | Yes - if using Standard Image or configured in custom image |
| Linux SSH access | No | Yes |
| Root access | No | Yes (via sudo) |
| Full system control | No | Yes |
| Data preservation | Yes (during recreate) | No - everything deleted during Terminate |
| Linux OS support | N/A | None |
| z/OS maintenance | Yes (during recreate) | Pull latest maintenance by pulling Standard z/OS image |
| Infrastructure support | Yes | Yes |
| Best for | Straight-forward application testing, CI/CD integration | Self-supporting ISVs with system administrator expertise |
CPU and memory sizes
Depending on the size of the instance, there is additional CPU and Memory made available to Linux which becomes visible when connected to Linux directly. The resources visible to Linux are:
- Small: 5 vCPU, 16 GB RAM
- Medium: 9 vCPU, 32 GB RAM
- Large: 13 vCPU, 64 GB RAM
IBM recommends reserving some vCPU and RAM for Linux and not committing it all in the zADE devmap, as doing so will directly impact performance negatively.
IBM z/OS standard image
HDISV instances come with a pre-configured IBM z/OS Standard Image that includes:
- z/OS base system - Current supported version with latest maintenance
- Development tools - IDzEE with DBB and Wazi Deploy, IBM Z Open Enterprise Foundation with USS tools including Git, Python, and ZOAU
- Optional middleware - Select DB2, CICS, IMS, or MQ during provisioning
- Pre-configured services - JES2, TCP/IP, catalogs ready to use
- Optimized performance - Fast startup and responsive operation
See z/OS System Layout for more information.
Storage
Default storage (600 GB)
Every HDISV instance includes 600 GB of storage divided into:
- System volumes (500 GB) - z/OS system files (recreated with updates)
- User volumes (100 GB) - Your applications and data (50 GB USER01 + 50 GB USMS01)
In Managed Service mode: Your user volumes (USER01 and USMS01) persist when you recreate the instance. System volumes are refreshed with the latest z/OS image.
In Linux Layer Access mode: All storage is managed by the user, only termination removes the storage.
Additional storage
Users can order additional storage through the ZLPN portal up to 1 TB total.
See Managing storage for details on monitoring usage and requesting more space.
Network and connectivity
VPN access required
All HDISV instances require VPN connectivity:
- Request VPN access through ZLPN portal
- Install VPN client on your workstation
- Connect to VPN before accessing your instance
- Use assigned IP address to connect
Static IP addresses
Each instance receives a static IP address that doesn't change. The IP can be used for:
- SSH connections
- 3270 terminal connections
- File transfers (SFTP/SCP)
- API access (RSE API, z/OSMF)
Connection methods
Managed Service mode:
- Connect directly to z/OS using the assigned IP
- SSH on port 22 (as
zosadmn) - 3270 terminal on port 2023
Linux Layer Access mode:
- Connect to Linux layer using the assigned IP
- SSH on port 22 (as
cloud-user) - Configure z/OS networking as needed
See Connecting to z/OS for detailed connection instructions.
Important considerations
Data management
Users are responsible for backing up user data. IBM does not perform any backups of HDISV environments.
- Export important datasets regularly using FTP, SFTP, or dataset migration tools
- Source code should be version controlled outside the system
- Git client is provided in the environment to facilitate source code management with user's existing/chosen Git server
- For an on-prem option, GitLab offers an open-source community edition
Maintenance and updates
The current maintenance schedule is bi-weekly with the exception of holidays. However, each Sunday is a reserved maintenance window between 9:30 AM and 3:30 PM U.S. Central Time for hardware maintenance purposes. During this window, system access may not be available. IBM sends optional notifications concerning upcoming maintenance windows or changes to support schedules. To be added to the notification list, please open a case in IBM Support, by selecting "Other contracted support services" in the Type of Support field, "IBM Z and LinuxONE Partner Network" in the Service field, and "Maintenance Notification" in the Case Title.
-
Managed Service: IBM performs all software maintenance on the IBM z/OS Standard Image. Maintenance is released for use during the Sunday maintenance window, but the updates are not pulled into each instance until the user initiates a system
recreate. -
Linux Layer Access: User manages all updates and maintenance (Users can pull the updated z/OS Standard image volumes with maintenance applied, or can bring updated ADCD maintenance).