Purpose

The mkvolumeattachment command allows you to create an attachment for an Exascale volume.

Syntax

mkvolumeattachment volume-id device-name --attributes { giClusterId=cluster-id | initiator=edv-initiator-id } [ --protocol edv ]

mkvolumeattachment volume-id iscsi-initiator-id --protocol iscsi [ --attributes attribute=value[,attribute=value] ... ]

Command Options

The options for the mkvolumeattachment command are:

• volume-id: Specifies the identifier for the Exascale volume for which you want to create an attachment. You can use the lsvolume command to find the identifier for each volume.
• device-name: For an Exascale Direct Volume (EDV) attachment only, specifies the device name to use in conjunction with the attachment. This is a user-supplied name, which is applied to the device file that is associated with the attachment. After attachment, the corresponding device file is located under /dev/exc/.

• --protocol: Specifies the attachment protocol, either edv or iscsi. If not specified, edv is assumed.

• iscsi-initiator-id: For an iSCSI attachment only, specifies the identifier used by iSCSI initiators to identify the attachment.

• --attributes: Specifies different attributes depending on the attachment type.

  • For a cluster-wide EDV attachment only, the giClusterId attribute specifies the Oracle Grid Infrastructure (GI) cluster ID associated with the volume attachment. When you specify this attribute, the corresponding device file is created on all nodes in the Oracle GI cluster.

  • For a node-specific EDV attachment only, the initiator attribute specifies the EDV initiator ID associated with the volume attachment. When you specify this attribute, the corresponding device file is only created on the cluster node associated with the specified EDV initiator ID.

  • For an iSCSI attachment only, specifies various attributes for the attachment. As a minimum, the following attributes are required for CHAP (Challenge Handshake Authentication Protocol):

    • chapUserId

    • chapPassword

    • chapMutualUserId

    • chapMutualPassword

Usage Notes

The following notes apply only to EDV attachments:

• During initial system deployment with Oracle Exadata Deployment Assistant (OEDA), the Exascale Direct Volume (EDV) service is configured on each Exadata compute node (bare-metal or VM) and is related to the Exascale user that manages the Oracle Grid Infrastructure (GI) cluster. To create an EDV attachment, you must use the Exascale user linked with the EDV service.

  If the GI cluster uses a non-role-separated user configuration with one Oracle OS user account, then the associated Exascale user is related to the EDV service. If the GI cluster uses a role-separated configuration with a Grid OS user account and an Oracle OS user account, then the EDV service is linked to the Exascale user associated with the Grid OS account.

  To find the Exascale user linked with the EDV service, use the ESCLI lsinitiator command with the --detail option and examine the user attribute.

• Each EDV attachment also has a kernel device file at /dev/exc-devN, where N is the minor number of the device. The kernel device name is contained as an attribute of the EDV attachment and is visible using the ESCLI lsvolumeattachment command. The relationship between the kernel device file and the user-named device file (under /dev/exc/) is also recorded in the udev database and is visible using the following Linux command:

  # udevadm info device-file

  For the device-file value, you can specify either the kernel device file (/dev/exc-devN) or the user-named device file (under /dev/exc/).

• By default, read and write access to EDV device files is only available to the root operating system user and members of the disk group. Depending on your use case, you may need to modify the permissions on the EDV device files before using them.

  For example, to make the EDV device file at /dev/exc/myvol readable and writable by the oracle user and dba group, you could configure it using a udev rule similar to the following:

  # cat /etc/udev/rules.d/57-edv-user.rules
  KERNEL=="exc-*", ENV{EXC_ALIAS}=="myvol", OWNER="oracle", GROUP="dba", MODE="0660"

• To facilitate the management of udev rules related to EDV devices, each EDV client node is configured with a template udev rules file at /etc/udev/rules.d/57-edv-user.rules, which you can modify to fulfill your requirements. To maintain existing udev rules, /etc/udev/rules.d/57-edv-user.rules is preserved whenever the EDV client software is updated.

• Each EDV client node can support a maximum of 1024 attachments at the same time. This limit includes the total of all cluster attachments involving the server, as well as local attachments specific to the server.

Examples