Hitachi Simple Modular Storage 100, User Manual

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Introduction
Hitachi Simple Modular Storage 100 User’s Guide
• Handling transmission of the packets and corresponding responses
using TCP/IP.
An iSCSI target is a device that receives iSCSI requests originating from an
iSCSI initiator. Typically, the target is a drive contained in a storage device,
such as your Hitachi Simple Modular Storage 100.
The following steps describe the sequence followed by the iSCSI initiator
and target when establishing a “session.”
1. The iSCSI initiator starts a TCP session with a target and tries to log in
by sending a list of log-in parameters.
2. The initiator and target may insist on authenticating each other with one
of several authentication methods (described next), depending on the
system's configuration.
3. After passing the authentication stage, the initiator and target negotiate
operating parameters, after which SCSI commands and data can pass
between them.
LUNs
Your Hitachi Simple Modular Storage 100 includes several drives, with each
drive including many gigabytes of storage. To effectively enable access to
this storage, it is organized into smaller portions called logical units or
volumes that can be allocated to different resources that want to access the
storage.
Each volume itself consists of a numeric address, thereby permitting the
storage on your Hitachi Simple Modular Storage 100 to appear as many
smaller storage units to the host computers accessing it, enabling more
efficient operation. To the server, a volume appears to be a single virtual
“disk”.
LUNs can be assigned to hosts, so that a particular volume can be accessed
only by designated hosts that have “permission” to access that portion of
the storage. This provides enhanced security as the software controlling
access to the storage system will only permit access by certain previously
defined hosts. While it is somewhat arbitrary how many hosts are permitted
to access a given volume, conventionally only one host usually has access
rights to a given volume at a given time. As a result, data on the volume is
protected against access by hosts or servers other than those previously
designated, thereby enhancing the security of the data.
CHAP
The Challenge Handshake Authentication Protocol (CHAP) is a security
mechanism that one entity uses to verify the identity of another entity,
without revealing a secret password that is shared by the two entities. In
this way, CHAP prevents an unauthorized system from using an authorized
system's iSCSI name to access storage.