SMI Tutorial > SMI-S 1.1.0 Functionality > SNIA Subprofiles > Storage Subprofiles > Masking and Mapping Subprofile

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Masking and Mapping Subprofile

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The Masking and Mapping Subprofile is referenced by other SNIA Storage Profiles as an optional enhancement. A SCSI storage device is identified by an assigned Logical Unit Number (LUN). If a storage device is divided into subsets of storage capacity, then each subset is assigned a separate Logical Unit Number (LUN).

Before a user can access data from a storage system on a SAN, a data path must be established between an initiator port on a host system through a target port on a storage system. The target port exposes the LUNs attached to it. In the absence of any restrictions, any initiator port on any host system can connect to any target port on any storage system and see all the LUNs attached to the target port.

Mapping and Masking mechanisms have been defined to impose controls on data access. Masking provides the ability to control which servers can access which LUNs. Typically, a storage system will restrict access to a LUN using a list of specific initiator port WWNs. Access can be read-only or read-write. A View represents the LUNs that an initiator port sees. Mapping provides the ability to expose a different View of LUNs to different host initiator ports. For example, different host initiator ports can see the same storage resource by a different LUN.

This Subprofile allows a Client to manage the access to the LUNs attached to the target ports on a storage system using the Masking and Mapping mechanisms. Using this Subprofile, a Client can do the following:

  • Ask to be notified when a LUN is activated or deactivated
  • Ask to be notified when a View is added or removed
  • Ask to be notified when access is granted or removed for an initiator port
  • Enumerate all of the existing LUNs
  • Enumerate all of the defined Views
  • Grant or remove access for a known initiator port
  • Create, modify or remove Views
  • Add or remove a known initiator ports that may be granted access to a LUN

The Masking and Mapping Subprofile can optionally enhance the following storage Profiles to provide this additional capability:

  • Array Profile - allows a Client to manage external RAID arrays and disk storage systems
  • Storage Virtualizer Profile - allows a Client to manage a RAID array that does not include any local storage

 

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