User guide

Technical white paper | HP Enterprise Virtual Array Storage and VMware vSphere 4.x and 5.x configuration best practices
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Table 2. HP EVA 1GbE iSCSI Module High Availability configuration decision chart
Used 1GbE Port per
controller
1
2
3
4
Used iSCSI targets
used per 1GbE port for
each LUN
1
2
1
2
1
2
1
2
Used NIC
ports per
host
1








2





x

x
3



x
x
x
x
x
4



x
x
x
x
x
 - Does not meet adequate high availability
- Meet adequate path count and high availability
x - Exceeds the ESX supported Max path per LUN – Does not meet adequate or symmetrical high availability
Table 2 is derived from the following facts:
• The 1GbE iSCSI Module has four ports per controller.
• A LUN that is exposed via iSCSI using EVA iSCSI Modules belongs to one and only of the four LUN groups.
• Each LUN group exposes its LUNs through two iSCSI targets and both iSCSI targets are accessible through all GbE
controller ports.
• A user can use one or all available GbE ports when configuring vSphere 4.x/5.x with HP EVA 1GbE iSCSI Module.
• A user can elect to only use one of the two iSCSI targets to access the LUNs within a LUN group.
HP EVA iSCSI connectivity provides a wide range of configuration options. Each option comes with a tradeoff between
increased path availability and increased GbE port bandwidth. In Table 2, the highlighted cell is the intersection of
configuration options that provides the best balance of high availability and GbE port bandwidth.
Best practices for 1GbE iSCSI Module configuration
• When all GbE ports are connected to the iSCSI SAN and two NICs are used at the host, use Static discovery to control the
host access to desired targets when using a 1GbE iSCSI Module option.
• To simplify configuration of the 1GbE iSCSI Module and meet adequate high availability, use Dynamic discovery at the ESX
host when only two NICs are accessing the iSCSI SAN and up to two GbE ports are used per controller.
The 10GbE iSCSI Module option on the other hand provides two 10GbE iSCSI ports for LUN access. For this it is safe to use
Dynamic discovery with a 10GbE iSCSI Module in all configurations as long as up to 2 NIC ports are used on the host side.
Table 3 below provides guidance on selecting the right number of paths at the host and the array in a 10GbE iSCSI Module
configuration with two distinct SANs as shown in Figure 11.
Table 3. HP EVA 10GbE iSCSI Module High Availability configuration decision chart
Used 10GbE Port per
controller
1
2
Used iSCSI targets
used per LUN
per 10GbE port
1
2
1
2
Used NIC
ports per
host
1




2




3



x
4



x
 - Does not meet adequate high availability
 - Meet adequate path count and high availability
x - Exceeds the ESX supported Max path per LUN – Does not meet adequate or symmetrical high availability