Service manual

Design considerations for Ethernet switches
The following information was qualied using the HP ProCurve switch. You must use the HP
ProCurve switch for iSCSI trafc. However, for control and FTP/streaming trafc, it is allowed to
use a different brand of switch, such as a Cisco Catalyst switch, if required by your site. If you are
using a non-HP switch, apply the information accordingly. Refer to the documentation you received
with the switch as necessary.
The primary factors that inuence the number and conguration 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 trafc does not cross between an “A” switch and a “B” switch, so if there are
Inter-Switch Links (ISLs) between redundant switches, media trafc does not use these ISLs.
• Separation of iSCSI trafc — Media (iSCSI) trafc must be kept separate from control trafc,
FTP/streaming trafc, and any other type of trafc. The recommended way to provide this
separation is to congure each switch to have two VLANs, with half the switch’s ports on each
VLAN. The media (iSCSI) trafc uses one VLAN and all other trafc uses the other VLAN.
This “other” trafc can include both FTP and control trafc, as it is allowed that they be on the
same VLAN. On very large multiple switch systems, designers with sufcient knowledge can
use other options for providing the separation of iSCSI trafc, such as using one switch or fabric
exclusively for media trafc and another switch or fabric exclusively for non-media trafc.
• FTP bandwidth — This is a consideration if using multiple switches that share the FTP trafc.
In this case you must use sufcient ISLs to provide the bandwidth needed to support your FTP
trafc load between switches. Only control trafc and FTP trafc use ISLs, but since FTP trafc
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 conguration for all K2 SANs. This
provides sufcient bandwidth for most FTP trafc 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
congurations are also available, as explained below.
Connect and congure ISLs only as specied 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 ve 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.
2013 07 20 K2 Installation and Service Manual 329
Administering and maintaining the K2 SAN