iSCSI protocol enables you to access storage devices as if they are connected to a local system. An Oracle Solaris system can act as either an iSCSI client (initiator) or a server (target).
TCP connections or iSCSI Extensions for RDMA (iSER) can be used to transfer iSCSI data in Oracle Solaris. iSER accelerates the iSCSI protocol by using Remote Direct Memory Access (RDMA) protocol to transfer data directly between the iSCSI nodes without intermediate data copies.
In Oracle Solaris, I/O multipathing is enabled by default and must not be disabled for iSCSI. When multiple iSCSI sessions are configured per target (MS/T), I/O multipathing combines these sessions to a single iSCSI device.
Using iSCSI initiator and targets in Oracle Solaris has the following benefits:
The iSCSI protocol runs across existing Ethernet networks.
You can use any supported network interface card (NIC), Ethernet hub, or Ethernet switch.
You can use the existing infrastructure and management tools for IP networks.
iSCSI can utilize InfiniBand (IB) infrastructure to access storage devices. You can use iSCSI on an existing IB infrastructure.
You can install the Oracle Solaris OS on an iSCSI disk. This iSCSI disk can also be used as a root file system to boot the OS. For more information about installing the OS on an iSCSI disk, see Installing Oracle Solaris 11.3 Systems.
The limitations of using the iSCSI initiator software in Oracle Solaris are as follows:
iSCSI targets cannot be configured as dump devices.
Sharing iSCSI traffic with other traffic can affect performance.
iSCSI initiator subsystem runs only on the global zone and not on 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. This limitation does not imply for kernel zone.
The iSCSI software and hardware requirements in Oracle Solaris are as follows:
Oracle Solaris storage software and devices.
The system/storage/iscsi/iscsi-initiator software package contains the iSCSI initiator management utilities.
If you are using TCP connection, use any supported NIC.
If you are using iSER, configure IB. For more information, see Chapter 3, Using InfiniBand Devices in Managing Devices in Oracle Solaris 11.3.
Consider the following iSCSI recommendations or considerations before configuring iSCSI devices in your network.
Deploy iSCSI devices in a fast and dedicated Ethernet network.
Use jumbo frames to allow more data transfer in each Ethernet transaction and reduce the number of frames.
Use multiple sessions per iSCSI target (MS/T) to increase performance. For more information about how to create multiple sessions for a target, see How to Enable Multiple iSCSI Sessions per Target.
Spread iSCSI sessions across multiple physical links or subnets for higher availability of iSCSI devices.
Use IP network multipathing (IPMP) for load spreading and better failover mechanism. For more information about failover mechanism in IPMP, see IPMP Support in Oracle Solaris in Administering TCP/IP Networks, IPMP, and IP Tunnels in Oracle Solaris 11.3.
Use iSNS target discovery to simplify configurations and to enhance security in a large setup. For more information about administer iSNS discovery method, see Administering Internet Storage Name Service Target Discovery Method.
Use CHAP authentication for additional security. For more information about configuring CHAP authentication, see Configuring Authentication in an iSCSI-Based Storage Network.