eG Monitoring
 

Measures reported by NAUSDIGroupTest

Initiator groups (igroups) are tables of host identifiers (FCP WWPNs or iSCSI node names) that are used to control hosts' access to LUNs.

igroups specify which initiators have access to which LUNs. igroups can be created either before or after LUNs are created, but they must be created before a LUN is mapped to an igroup. Initiator groups can have multiple initiators, and multiple igroups can have the same initiator. However, a LUN can not be mapped to multiple igroups that have the same initiator.

An initiator cannot be a member of igroups of differing ostypes.

This test reveals if any mismatch of the cluster failover setting has occurred between the local and partner systems of a cluster and also reports the configuration measures listed below:

  • How many initiator groups have an incompatible operating system?
  • How many initiator groups are with an invalid use partner setting?
  • How many initiator groups have an operating system that is incompatible with the use partner setting and the VSA setting?
  • How many initiator groups have the ALUA setting mismatch between the local and partner systems?

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Cf_mode_mismatch Indicates whether/not the cluster failover setting of the local system is different from that of the partner system.   In a cluster setup of the storage systems, the Cluster failover modes of the systems in that cluster need to match so that the cluster failover would function appropriately. This measure indicates a value Yes if the cluster failover setting is different in the local system and the partner system and a value No if the settings are same in both the local system and the partner system.

The values reported by this measure and their numeric equivalents are available in the table below:

Numeric Value Measure Value
0 No
1 Yes

Note:

This measure reports the above-mentioned Measure Values to indicate whether/not the cluster failover setting of the local system is different that of the partner system setting. However, the graph of this measure will be represented using the corresponding numeric equivalents i.e., 0 or 1.

The Detailed Diagnosis of this measure shows the mismatching local and partner Cluster Failover modes.

OS_type Indicates the number of initiator groups whose Operating system is not compatible with that of the configured fcp cfmode. Number Some host operating systems are compatible with certain selective fcp cfmodes only. In such a scenario, the OS type of the initiator group must match the fcp cfmode for proper functioning of the initiator group.

The Detailed Diagnosis of this measure indicates the name of the initiator group and the OS type of the initiator group.

Use_partner_setting Indicates the number of initiator groups with an invalid use-partner setting i.e., the use partner setting of the initiator group is not compatible with that of the configured fcp cfmode. Number The use-partner setting indicates whether the initiators in the initiator group are allowed to use the partner's port in a cluster setup. Initiator groups with an invalid use-partner setting can result in some hosts losing LUNs during takeover.

The Detailed Diagnosis of this measure indicates the name of the affected initiator group and the use partner setting of that corresponding initiator group.

Use_partner_OS Indicates the number of initiator gropus whose use partner setting is not compatible with their configured operating system. Number In a cluster setup, in order to ensure proper behaviour of the Storage systems during failover, the host operating sytems are designed to support only certain use parameter settings. A diiference in the use parameter setting may result in performance bottleneck.

The Detailed Diagnosis of this measure highlights this incompatibility issue by listing out the initiator group, OS type and the use parameter setting of that initiator group.

Alua_setting Indicates the number of initator groups for which the ALUA setting do not match between the local and the partner unified storage systems. Number ALUA is a T10 standard that specifies the access characteristics (in terms of performance and supported SCSI commands) of a Logical Unit that can be accessed through more than one target port. ALUA is typically used by host multi-path software to recognize primary and secondary paths to a Logical Unit when more than one path are available to the Logical Unit. If the ALUA setting does not match between the local and partner filers, it would affect the host multi-path software's ability to distingush the primary and secondary paths which could lead to the poor performance of the system.

The Detailed Diagnosis of this measure provides the name of the affected initiator group and the status of the ALUA (whether enabled or disabled) in the local and partner storage systems.

VSA_setting Indicates the number of initiator groups with the VSA setting that do not match with that of the configured operating system. Number The Volume Set Addressing (VSA) setting is enabled only for the initiator groups that are configured with the HPUX operating system. Incorrect sertings of the VSA may deny access to the hosts for some/all LUNs.

The Detailed Diagnosis of this measure indicates the name of the initiator group, the operating system of the initiator groups and the status (whether enabled/disabled) of the VSA setting.