The primary factors that influence the number and configuration of switches on a K2 SAN are as
follows:
• Redundancy — Non-redundant K2 SANs have only one media (iSCSI) network and can operate
with a single switch. Redundant K2 SANs have an “A” media network and a “B” media network
and require at least two switches, so that the A network and the B network never share the same
switch. Media traffic does not cross between an “A” switch and a “B” switch, so if there are
Inter-Switch Links (ISLs) between redundant switches, media traffic does not use these ISLs.
• Separation of iSCSI traffic — Media (iSCSI) traffic must be kept separate from control traffic,
FTP/streaming traffic, and any other type of traffic. The recommended way to provide this
separation is to configure each switch to have two VLANs, with half the switch’s ports on each
VLAN. The media (iSCSI) traffic uses one VLAN and all other traffic uses the other VLAN.
This “other” traffic can include both FTP and control traffic, as it is allowed that they be on the
same VLAN. On very large multiple switch systems, designers with sufficient knowledge can
use other options for providing the separation of iSCSI traffic, such as using one switch or fabric
exclusively for media traffic and another switch or fabric exclusively for non-media traffic.
• FTP bandwidth — This is a consideration if using multiple switches that share the FTP traffic.
In this case you must use sufficient ISLs to provide the bandwidth needed to support your FTP
traffic load between switches. Only control traffic and FTP traffic use ISLs, but since FTP traffic
is more variable and has potentially higher bandwidth needs, it is the primary consideration when
designing ISLs. You do not need to consider iSCSI bandwidth on ISLs.
Using three 1 Gig ISLs to connect switches is the default configuration for all K2 SANs. This
provides sufficient bandwidth for most FTP traffic loads. The10 Gig ports on the switch connect to
the K2 Media Server and are available for connection to the optional NH server. Other ISL
configurations are also available, as explained below.
Connect and configure ISLs only as specified in the following table, taking your FTP bandwidth
into consideration:
Trunk/ISLs requiredMaximum FTP bandwidth
A trunk with three 1 Gb/s ISLsLess than 100 MB/sec
A trunk with five 1 Gb/s ISLs100 - 300 MB/sec
A trunk with two 10 Gb/s ISLsMore than 300 MB/sec
NOTE: One Gig ISLs must be an odd number (3 or 5).
• Port count — The number of client connections, FTP/streaming connections, and other connections
determine how many ports are required. As the port count increases, you must use switches with
more ports and/or multiple switches. When multiple switches are used, the port count assigned
to each VLAN and the ports used for ISLs must be considered.
Based on these factors, determine the number of switches, the number of ports on each switch, and
the ISLs required for your system needs. You can find procedures for configuring the HP ProCurve
switch in the chapters elsewhere in this manual for installing each level. Adapt the procedures
according to your switch design as you configure your switches.
334 K2 SAN Installation and Service Manual 02 February 2012
Administering and maintaining the K2 SAN
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