Best Practices: Configuring an iSCSI Network for an Rapid Recovery Repository (4033593)

Users may experience delays and frequent network drops on a repository that resides in an iSCSI storage area network (SAN).

iSCSI is a protocol that uses TCP to transport SCSI commands, enabling the use of the existing TCP/IP networking infrastructure as a SAN. The Microsoft iSCSI initiator enables users to connect a host computer that is running Windows Server to an external iSCSI-based storage array through an Ethernet network adapter. In order for an iSCSI network to function properly and to avoid any latency issues, Quest recommends users follow best practice guidelines for installing an iSCSI network.

Complete the following steps:

• The network should be isolated from the regular data network. Typical network applications are designed to account for potential network failures; however, operating systems expect their disk drives to be available at all times. An infected laptop that overloads the network for a few minutes could cause an issue with servers that can’t access their disks. The most important thing to remember when configuring an iSCSI SAN is to place iSCSI traffic on its own VLAN, preferably on a completely separate, gigabit-speed network. The iSCSI SAN should use an enterprise-class, non-blocking, gigabit Ethernet switch with dual, redundant power supplies.
• The iSCSI NIC on the Core should be configured as below. These settings should not be applied on the data NIC.
  • iSCSI network properties should be set to Internet Protocol Version 4.
  • Register this connection’s address in DNS should not be selected and Disable NetBIOS over TCPIP should be selected.
  • Access the advanced properties of each iSCSI network card and set the Checksum offload for “IPV4”, “Large Send Offload”, “TCP Checksum Offload” and “UDP Checksum Offload” as Disabled. Set the jumbo packets to 9014 Bytes.
  • Run the NetSH commands to set the offload settings globally
    • Netsh int tcp set global RSS=Disabled
    • Netsh int tcp set global chimney=Disabled
    • Netsh int tcp set global autotuninglevel=Disabled
    • Netsh int tcp set global congestionprovider=None
    • Netsh int tcp set global ecncapability=Disabled
    • Netsh int ip set global taskoffload=disabled
    • Netsh int tcp set global timestamps=Disabled
    • Netsh int tcp set global netdma=disabled