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How to start using the iSCSI target service on Synology NAS

Last updated:Apr 19, 2023

How to start using the iSCSI target service on Synology NAS

Purpose

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

Resolution

  1. Sign in to DSM as the administrator.
  2. Go to SAN Manager (DSM 7)/iSCSI Manager (DSM 6.2) > 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 iSCSI (DSM 7)/Target (DSM 6.2), 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. (For DSM 7) Set the permissions for the LUN. Choosing Allow all will by default grant the read/write permission to all hosts and initiators. Make sure you configure the permissions for each host/initiator properly if you choose Custom.4
  7. 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. The Discovery process on the iSCSI initiator may fail if the CHAP authentication on your NAS is enabled. To avoid this, you can do one of the following:
    • (For DSM 7) Enable and configure Global iSCSI CHAP in SAN Manager > Settings > iSCSI Service. Keep in mind that individual target CHAP settings will be overridden when this option is enabled.
    • Complete the Discovery first, and then enable CHAP authentication before connecting to a target.
    • Connect to a target with the IP and IQN.
  4. If you choose Custom, only listed hosts can access the LUN. This can be modified anytime after the LUN is created.