Post by Venkatesh Periyasamy on Apr 20, 2017 10:11:36 GMT
As per the specification(1.0.3),Under Storage Group Resource(5.9), ServerEndPointGroup is defined as follows.
The set of server endpoints to which the volumes can be exposed is specified by the ServerEndpointGroupsattribute. The ServerEndpointGroup resource specifies a collection of EndpointGroup resources.
Here the ServerEndPointGroup may contain more than one endpoints through which the volume/LUN can be exposed. i.eone LUN/Volume can be exposed to multiple iSCSI targets(EndPoints). This may lead to data corruption also.
Is there any other reason behind defining multiple server endpoints to single LUN/Volume? Is there any attribute/class maps LUN to specific ServerEndPoint (One-To-One) rather than doing it as a group?
Q1: Is there any other reason behind defining multiple server endpoints to single LUN/Volume?
A1: This functionality supports a very common scenario for network based storage known as multi-pathing. In SCSI, this is supported by a feature known as Asynchronous Logical Unit Access (ALUA). Typically access to these multiple paths is serialized by a multi-path driver on the initiator side. The multi-path driver is responsible for recognizing that a logical unit (volume) has been exposed via multiple paths. The multi-path driver then generally presents the volume as a single logical disk to the operating system.
Q2: Is there any attribute/class maps LUN to specific ServerEndPoint (One-To-One) rather than doing it as a group?
A2: No. This functionality is used for SAN access to a Volume and there are typically multiple paths to support availability and performance considerations. Note 1: StorageGroup has a ClassOfService. The availability and performance aspects of that ClassOfService should govern the minimum number and type of server side endpoints configured by the service implementation.