Dell PowerVault MD3000i - Manual (Page 23)

Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices
December 2008 – Revision A01 Page 23
5 Considering the Host Server(s)
5.1 Host Hardware Platform
5.1.1 Considering the Server Hardware Architecture
Available bandwidth depends on the server hardware. The number of buses adds
to the aggregate bandwidth, but the number of HBAs sharing a single bus can
throttle the bandwidth. Additionally, some server hardware has slower-speed PCI-
E ports (4x) as well as high-speed ports (8x). The Dell SAS5e HBAs are PCI-E 8x
devices and should be installed in 8x slots for maximum performance. Where
additional PCI-E slots are available, two SAS HBAs should be used to redundantly
attach the I/O host to each storage array controller module to maximize both
performance and redundancy.
Note : Dell™ provides a bus layout on the lid of all servers. Consult this chart and
use a different bus for each HBA installed in the Host.
5.1.2 Sharing Bandwidth on the Dell™ MD3000i with Multiple NICs
Consider the following when sharing bandwidth on MD3000i with multiple NICs.
• Give each NIC its own IP address.
• Connect each NIC to a separate switch, or direct attach host NIC(s) to
target iSCSI port(s).
• Use separate NICs for public network access than the storage array iSCSI
session. Install additional NICs as needed.
• Ensure the use of separate redundant networks dedicated for iSCSI traffic,
if this is not possible, setup a separate VLAN for iSCSI traffic.
• Use Jumbo Frames (Jumbo Frames increase the TCP frame size from
1500 bytes to 9000 bytes).
• The Microsoft iSCSI initiator will not work with teamed NICs.
• A single Host cannot mix HBAs and NICs to connect to the same or
different arrays.
To edit the Jumbo Frames settings in the MDSM, select the iSCSI tab,
Configure iSCSI Host Ports, Advanced
(see Figure 11). Jumbo Frames can be
also be set using the CLI. If using an MD3000i with Jumbo Frames, ensure the
Ethernet switches and host NIC(s) also have Jumbo Frames enabled and are set
to an equivalent value.