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How do I use the iSCSI service on Synology NAS (DSM 6.2)?

Last updated:Jun 17, 2025

How do I use the iSCSI service on Synology NAS (DSM 6.2)?

Purpose

iSCSI is a protocol to facilitate SCSI-based storage commands to be sent over ubiquitous network structures. Using the iSCSI service provides an illusion that a hard drive is locally attached to a computer, and will be managed by computer or host, and will be managed by their operation system. This article will guide the administrator through the basics of creating a LUN and iSCSI target on Synology NAS.

Environment

  • DSM 6.2 series

Resolution

  1. Sign in to DSM as the administrator.
  2. Go to iSCSI Manager > LUN and click Create.
  3. Specify the following information for the LUN. Click Next to continue.
    • Name: Enter a name for the LUN.
    • Location: Specify where the LUN will reside.
    • Total Capacity: Enter the capacity of the LUN in Gigabytes.
    • Space Allocation: Thick Provisioning provides better stability in LUN performance. Thin Provisioning provides on-demand-allocation ability and all advanced features.1
    • Advanced features: Advanced features deliver abilities including taking snapshots and space reclamation. Hardware-assisted zeroing, locking, and data transfer provide functions for VMware VAAI and Windows ODX. For more information on the advanced features, refer to Terminologies in the help article.
  4. Under Target, choose between Create a new iSCSI target, Map existing iSCSI targets, or Map later. Here we will choose Create a new iSCSI target as an example. Click Next to continue.
  5. Specify the following information for the iSCSI target. Click Next to continue.
    • Name: Enter a name for the iSCSI target.
    • IQN: Enter the IQN for the iSCSI target.2
    • Enable CHAP:3 CHAP will require iSCSI Initiators to be authenticated before using the iSCSI target; Mutual CHAP will require both initiators and targets to authenticate each other before facilitating communications. Enter the username (up to 12 characters, including letters or numbers) for the authentication and the password (12 to 16 characters, including letters or numbers).
  6. Confirm the settings and click Done to finish the wizard.

Notes:

  1. Thin Provisioning may cause the file system to crash when the volume runs out of space.
  2. There can be up to 128 characters in the IQN, including letters, numbers, colons, dashes, and periods.
    • Format Structure: iqn.yyyy-mm.domain:device.ID
    • Example: iqn.2010-10.Synology-iSCSI:VirtualDisk.01
  3. iSCSI Discovery may fail if CHAP authentication uses credentials different from those of the iSCSI target. To proceed, complete discovery before enabling CHAP authentication, or connect directly to the target using its IP address and IQN from the initiator.