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Make sense of iSCSI.

iSCSI Hub
Independent · 2026
Isometric navy storage enclosure holding stacked drive bays with glowing pink trays, set on a dotted grid of network nodes, evoking disks backing an iSCSI LUN Featured
fundamentals

What Is an iSCSI LUN? What Backs It and Who Owns It

An iSCSI LUN is a block volume inside a target that one host sees as a raw local disk. What backs it, how mapping works, and when to skip it.

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iSCSI hands a client a raw disk instead of a share, and almost every problem people hit with it comes from that one difference. These four pages cover it in the order the questions usually arrive.

The guides cover iSCSI SAN targets, MPIO multipathing and LUN provisioning. Begin with the ownership model, choose the protocol your application needs, then follow the target and client configuration for your platform. For an existing connection problem, start with the troubleshooting guide and the message your initiator reports.

  1. 1 · Understand it
    What is an iSCSI LUN?

    What an IQN identifies, what a LUN really is, and why MPIO and link aggregation are not the same mechanism.

  2. 2 · Decide
    iSCSI vs NFS vs SMB

    Block or file, and what changes with it: locking, path redundancy, authentication and how each one behaves when the storage disappears.

  3. 3 · Build it
    iSCSI target setup on Unraid, TrueNAS and Synology

    Unraid plugin and pool placement, TrueNAS zvol mappings, Synology SAN Manager, and connecting Proxmox as an initiator.

  4. 4 · Fix it
    Login, timeout and path errors

    Portal, discovery, login, ACL, CHAP, MTU, then the timers that decide when a dead path becomes a filesystem error.

iSCSI Throughput and MPIO Calculator Free, in-browser: path count, block size and media class against the link ceiling.

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