An Initiator is the storage device/endpoint that initiates SCSI request. Typically, Initiator serves the same purpose what SCSI adapter does. The only difference is, instead of physically cabling SCSI devices (like HDD, Tape Drives), an SCSI initiator send SCSI commands over an IP/Fiber Channel network.
Pluggable storage architecture was one of the major enhancement done by VMware to provide two key functions of the storage component in vSphere world.
• Multipathing: If there are multiple paths, which paths should be used for given I/O
• Failover: When a path goes down, I/O should failover to alternative path automatically.
The connection from the server through the HBAs to the Storage Controller is referred as PATH. Multipath Connectivity refers to a system configuration where multiple connection paths exists between Server and Storage Device called LUNs within a Storage Subsystem.
In this article, we will be discussing about commonly asked questions like:
1. What is Zoning and Why do we need it?
2. Difference between Soft Zoning and Hard Zoning?
3.On which component of Datacenter, Zoning is defined at?
4.What is LUN masking and Why do we need it?
5.How LUN masking is different from Zoning?
6.Where do we configure LUN masking?
When single resource is being shared across multiple objects/Users then we need some control mechanism for helping us to avoid any kind of confliction/unnecessary congestion while claiming that resource. That’s what exactly being solved by Reservation.
Reservation restrict other users to claim resource which is already being allocated or used by another user.
ALUA is type of storage device that is capable of servicing IO to given LUN on two different Storage Processors but in an uneven manner. ALUA is also known as Asymmetric Active/Active Arrays. Active/Active -> Both the Controller ports receives IO Commands to LUN. Asymmetric -> Only one controller which is owning the LUN can issues IO to that LUN.
