Network Latency; Network Bandwidth - HP P6000 Installation Manual

Key configuration notes:
Switch infrastructure: Use dual redundant 1 or 10 gigabit switches trunked together for
bandwidth and fault-tolerance.
iSCSI and iSCSI/FCoE module connectivity: Ensure at least one port from each module is
connected to each switch.
Host server connectivity: Use dual NICs connected to the IP storage network with a single port
connected to each switch. For Windows 2003/2008, use HP DSM for MPIO for multiple NIC
support.

Network latency

High network latency can be the primary cause of slow I/O performance or iSCSI drive disconnects.
It is important to keep network latency (for example, ping response time measurement) on the
IP-SAN subnet below two milliseconds. Many factors can contribute to increasing network latency;
the most common being congestion, distance, and router hops. Configuring the IP-SAN on a single
IP subnet with Layer-2 switching can help lower network latency.

Network bandwidth

Network bandwidth required for an IP-SAN depends on the server applications, maintenance
utilities, and backup/recovery processes. Most I/O intensive applications, like Microsoft Exchange
and SQL Server, do not consume much network bandwidth but are more sensitive to network
latency issues. Bandwidth becomes more important during maintenance operations, like
backup/recovery. Any sequential read/write stream could consume significant bandwidth.
NOTE: Storage data transfer rates are typically measured in bytes, while network data transfer
rates are measured in bits. A 1 Gb/sec network connection can transfer a maximum of 120–130
MB/sec. Microsoft Windows provides performance monitor counters that can help determine the
data-path bandwidth requirements. Disk bytes/sec is the rate bytes are transferred to or from the
disk during write or read operations.
The P6300/P6500 EVA is available as a single protocol (FC) or as a multi-protocol (FC/iSCSI or
FC/iSCSI/FCoE) array. The iSCSI protocol transport is supported at 1 GbE and 10 GbE rates
through the 1 GbE iSCSI modules or 10 GbE iSCSI/FCoE modules.
the normal multi-protocol data and management connectivity. HP P6000 Command View requires
Ethernet access to the 1 GbE iSCSI modules and can also use array-based management with the
management module or in-band host-based management with the FC, iSCSI, or FCoE connectivity.
Figure 1 (page 10) illustrates
Plan your storage configuration 9