ISCSI introduction
iSCSI is an industry standard protocol which allows sharing of block storage over Ethernet. It is a protocol for communicating with I/O devices, chiefly storage devices. iSCSI is an IP-based standard for connecting data storage devices over a network and moving data by carrying SCSI commands over IP networks. In simple words, iSCSI is an interface for communication between initiator and target.
Why ISCSI use TCP/IP ?
There is no packet loss while transferring data, if there is any loss, it is handled by the TCP/IP stack in the operating system.
The iSCSI protocol is a mapping of the SCSI remote procedure invocation model over the TCP protocol.
ISCSI Benefits
iSCSI provides cheap connectivity as compared to fiber channel FC. since there is NO need extra hardware Like HBA or SAN storage
An existing network can be used for iSCSI implementation. for best utilized of remote storage
- As iSCSI is used for block storage, it is very fast.
- IT administrators don’t need a lot of training on iSCSI storage since it is very easy to understand and implement.
- iSCSI is an IP-based protocol. It is FULLY based of TCP/IP and Ethernet.
iSCSI Components
- iSCSI Initiator– The client machine within a storage network is an iSCSI Initiator. The initiator can connect to the target by forming a session among them and can send iSCSI commands.
- iSCSI Target– The server machine within a storage network is an iSCSI target. An iSCSI target is any machine that receives iSCSI commands from an initiato
ISCSI Network Diagram
to understand ISCSI – lets to have a look to Pioneers Diagram above
we have windows server called iscsi103 with
- RIAD HDD with capacity 15TB
- interface for management with DMZ [server farm ] : with ip address 172.16.100.103
- interface for ISCSI target with DMZ [switch 3 ] : with ip address 172.21.102.103
- interface for redundant ISCSI target with DMZ [switch 3 ] : with ip address 172.21.103.103
also : we have ESXI host server called ESXI151 with
- interface for management with DMZ [server farm ] : with ip address 172.16.100.151
- interface for ISCSI target with DMZ [switch 3 ] : with ip address 172.21.102.151
- interface for redundant ISCSI target with DMZ [switch 3 ] : with ip address 172.21.103.151
also : we have ESXI host server called ESXI152 with
- interface for management with DMZ [server farm ] : with ip address 172.16.100.152
- interface for ISCSI target with DMZ [switch 3 ] : with ip address 172.21.102.152
- interface for redundant ISCSI target with DMZ [switch 3 ] : with ip address 172.21.103.152
also : we have ESXI host server called ESXI153 with
- interface for management with DMZ [server farm ] : with ip address 172.16.100.153
- interface for ISCSI target with DMZ [switch 3 ] : with ip address 172.21.102.153
- interface for redundant ISCSI target with DMZ [switch 3 ] : with ip address 172.21.103.153
server ISCSI103 will act as ISCSI Target
while each ESXI host [ESXI151,ESXI152,ESXI153] will act as ISCSI initiator
Conclusion
in this article we have got an over view about ISCSI storage and how ESXI host integrate with ISCSI
next article we will see how to configure ESXI to connect to ISCSI storage , please press here
