addvdiskaccess

Use the addvdiskaccess command to add an I/O group (or groups) to the set of I/O groups in which a volume can be made accessible to hosts.

Syntax

Read syntax diagramSkip visual syntax diagram addvdiskaccess -iogrp  iogrp_id_listiogrp_name_list -allowmismatchedscsiids vdisk_idvdisk_name

Parameters

-iogrp iogrp_id_list | iogrp_name_list
(Required) Specifies a list of I/O groups to add to the I/O group volume access set.
-allowmismatchedscsiids
(Optional) When you add new access I/O groups, this parameter allows the SCSI LUN IDs to be different than the currently assigned SCSI LUN IDs in existing access I/O groups.
vdisk_id | vdisk_name
(Required) Specifies the volume to which to add access through the specified I/O groups.

Description

If an I/O group is already a member of the access set, no error is generated and no action is taken for that I/O group. All host mappings for the volume are added to the I/O groups in the list. The -force option is not required to extend additional mappings to other I/O groups.

When an I/O group is added to the access set, it creates access to the volume from the hosts that are mapped to the volume from the nodes in the I/O group. If the volume is mapped twice, it is also mapped twice through all additional I/O groups.

You can add I/O groups to the volume access list if they are mapped to iSCSI hosts. This means that iSCSI hosts can access volumes that are accessible through multiple I/O groups (as well as a single I/O group).

Remember: The -addvdiskaccess command fails if:
  • Any host (for which the volume has a host mapping) is not associated with an I/O group in the list.
  • The host volume mapping limit is exceeded.
  • The number of extra mappings added exceeds the clustered system limit for host volume mappings.
  • If the protocol is set to NVMe and results in a volume that has more that one access I/O group, due to a limitation in the protocol.
  • If the same SCSI LUN ID is not available in the new access I/O group.
Two mappings are created if a host is mapped to a volume with two I/O groups. Hosts are limited to 512 host-to-volume mappings, which means a host can be mapped to:
  • 512 volumes in a single I/O group
  • 256 volumes across two I/O groups
  • 64 volumes across four I/O groups

The command fails if any host mapped to the volume is detected as a host system that does not support volumes mapped from multiple I/O groups.

The system assigns the same SCSI LUN ID allocated to the volume in other access I/O groups if it is available in the new access I/O groups. Using the -allowmismatchedscsiids parameter allows the system to allocate non-identical SCSI LUN IDs in the access I/O group. The lowest value available in each access I/O group is used. It might not be the same in all access I/O groups. Make sure that the host supports this configuration. This parameter is not supported for NVMe hosts. When a volume is mapped to a host that uses the NVMe protocol, the volume namespace ID (NSID) is assigned by the system. When you add access to a volume that already has different SCSI LUN IDs in its existing access I/O group, you must use -allowmismatchedscsiids or the command fails.

An invocation example

This example adds I/O group 2 to the volume access set for DB_Volume:

addvdiskaccess -iogrp 2 DB_Volume

The resulting output:

No feedback

An invocation example

This example adds I/O groups 2 and 3 to the volume access set for volume ID 3:

addvdiskaccess -iogrp 2:3 3

The resulting output:

 No feedback