iSCSI is an acronym for Internet SCSI (Small Computer System Interface), an Internet Protocol (IP)-based storage networking standard for linking data storage subsystems.
By carrying SCSI commands over IP networks, the iSCSI protocol enables you to access block devices from across the network as if they were connected to the local system.
The following solutions are available to use storage devices in your existing TCP/IP network:
iSCSI block devices or tape – Translates SCSI commands and data from the block level into IP packets. Using iSCSI in your network is advantageous when you need to have block-level access between one system and the target device, such as a tape device or a database. Access to a block-level device is not locked so that you can have multiple users or systems accessing a block-level device such as an iSCSI target device.
NFS – Transfers file data over IP. The advantage of using NFS in your network is that you can share file data across many systems. Access to file data is locked appropriately when many users are accessing data that is available in an NFS environment.
Here are the benefits of using iSCSI targets and initiators in Oracle Solaris:
The iSCSI protocol runs across existing Ethernet networks.
You can use any supported network interface card (NIC), Ethernet hub, or Ethernet switch.
One IP port can handle multiple iSCSI target devices.
You can use existing infrastructure and management tools for IP networks.
You might have existing Fibre-Channel devices that can be connected to clients without the cost of Fibre-Channel HBAs. In addition, systems with dedicated arrays can now export replicated storage with Oracle Solaris ZFS or UFS file systems.
The protocol can be used to connect to Fibre Channel or iSCSI Storage Area Network (SAN) environments with the appropriate hardware.
Here are the current limitations or restrictions of using the iSCSI initiator software in Oracle Solaris:
Support for iSCSI devices that use SLP is not currently available.
iSCSI targets cannot be configured as dump devices.
Transferring large amounts of data over your existing network can have an impact on performance.
The iSCSI initiator subsystem runs only on the global zone and not on the non-global zones. The workaround to access the iSCSI devices from within a non-global zone is to configure an iSCSI initiator in a global zone and add the device to a non-global zone by using the add device command during zone configuration.