Volumes: Block Storage and iSCSI Configuration
Block storage model
Nutanix Volumes presents block storage over iSCSI. A Volume Group is a collection of vDisks and becomes an iSCSI target with LUNs. External hosts such as ESXi, Hyper-V, or physical servers connect through the iSCSI data services IP. Configure an initiator IQN allowlist and optionally CHAP authentication.
Configuration steps
- Create a Volume Group and add the required vDisks.
- Attach the Volume Group to allowlisted initiators.
- On the host, add the iSCSI target portal using the data services IP, then discover LUNs.
- Format the LUN with the host file system, such as VMFS, NTFS, or ext4.
- Use multipathing and verify every path.
- Protect the Volume Group with snapshots or a protection domain for crash-consistent copies.
Worked example
An ESXi host sees no LUN. First confirm that the ESXi IQN is in the Volume Group allowlist. Next verify that the host can reach the iSCSI data services IP on TCP 3260 and that CHAP secrets match. After correcting the allowlist or CHAP, rescan the storage adapter. Using the Prism UI address instead of the data services IP is a common cause of discovery failure.
Traps
Do not use the Prism management IP as the iSCSI portal. Do not forget the IQN allowlist. A CHAP mismatch can block discovery even when the network is reachable. Volume Group snapshots are not application-consistent unless the application is quiesced.
Key points
- Volumes provides block storage over iSCSI.
- A Volume Group is a set of vDisks presented as an iSCSI target.
- Hosts connect through the iSCSI data services IP.
- IQN allowlists and CHAP control initiator access.
- Multipathing and quiescing are important for resilience and consistency.