iSCSI Commands and Information

Block volumes attached with the iSCSI attachment type use the iSCSI  protocol to connect a volume to an instance. See Volume Attachment Types for more information about volume attachment options.

Once the volume is attached , you need to log on to the instance and use the iscsiadm command-line tool to configure the iSCSI connection. After you configure the volume, you can mount it and use it like a normal hard drive.

To enhance security, Oracle enforces an iSCSI security protocol called CHAP  that provides authentication between the instance and volume.

Accessing a Volume's iSCSI Information

When you successfully attach a volume to an instance, Block Volume provides a list of iSCSI information. You need the following information from the list when you connect  the instance to the volume.

  • IP address

    When an IP address is assigned to a volume attachment, it is a valid IP address and an iSCSI connection can be made to it. Block Volume does not guarantee the order the IP address is assigned.
  • Port
  • CHAP user name and password (if enabled)
  • IQN

The CHAP credentials are auto-generated by the system and cannot be changed. They are also unique to their assigned volume/instance pair and cannot be used to authenticated another volume/instance pair.

The Console provides this information on the details page of the volume's attached instance. Click the Actions icon (three dots) on your volume's row, and then click iSCSI Information. The system also returns this information when the AttachVolume API operation completes successfully. You can re-run the operation with the same parameter values to review the information.

See Attaching a Volume and Connecting to a Volume for step-by-step instructions.

Recommended iSCSI Initiator Parameters for Linux-based Images

iSCSI attached volumes for Linux-based images are managed by the Linux iSCSI initiator service, iscsid. Oracle Cloud Infrastructure images use iSCSI default settings for the iscsid service's parameters, with the exception of the following parameters:

  • node.startup = automatic
  • node.session.timeo.replacement_timeout = 6000
  • node.conn[0].timeo.noop_out_interval = 0
  • node.conn[0].timeo.noop_out_timeout = 0
  • node.conn[0].iscsi.HeaderDigest = None

If you are using custom images, you should update the iscsid service configuration by modifying the /etc/iscsi/iscsid.conf file.