Zoning vind plaats op de SAN switch en masking vind plaats op de Storage array.
De oplossingen om initiators & targets te grouperen zijn: zoneren (1 initiator & multiple targets), igroup (WWPNs or IQNs) en Port sets (LIFS).
Een iGROUP is een manier om hosts/initiators (HBAs, NICs) te groeperen tot welke LUNs deze toegang hebben. Er is hier sprake van LUN masking.
LUN masking mechanism allows you to make LUNs available to some initiators and unavailable to others.
NetApp omschrijving van igroups:
Initiator groups (igroups) are tables of FC protocol host WWPNs or iSCSI host node names. You can define igroups and map them to LUNs to control which initiators have access to LUNs.
Typically, you want all of the host’s HBAs or software initiators to have access to a LUN. If you are using multipathing software or have clustered hosts, each HBA or software initiator of each clustered host needs redundant paths to the same LUN.
You can create igroups that specify which initiators have access to the LUNs either before or after you create LUNs, but you must create igroups before you can map a LUN to an igroup.
Initiator groups can have multiple initiators, and multiple igroups can have the same initiator. However, you cannot map a LUN to multiple igroups that have the same initiator.
Note: An initiator cannot be a member of igroups of differing ostypes.
Wat een port set(s) is:
Portsets limit host access to certain paths when they are bound to: An igroup
A Portset contains an access list consisting of LIFs
Command to group initiators to allow to be mapped to LUNs: igroup create
Over iGROUP throttles:
Data ONTAP implements a mechanism called igroup throttles, which you can use to ensure that critical initiators are guaranteed access to the queue resources and that less-critical initiators are not flooding the queue resources.
Operations using IGROUP throttles on a NetApp:
- To assign a specific percentage of the queue resources on each physical port to the igroup
- To reserve a minimum percentage of queue resources for a specific igroup
- To limit the number of concurrent I/O requests an initiator can send to the storage system
- To restrict an igroup to a maximum performance of use
Igroups, port sets and LUN mappings are replicated across the SAN replicated database ring.
- Igroups, port sets and LUN mappings
SAN management daemon process heet: bcomd.
Lees: What a cluster replication ring is: