Dell SC4020, Руководство по развертыванию

Страница: 180 / 184

• All devices used to connect iSCSI devices must support 9K jumbo frames. Every switch, router, WAN
accelerator, and any other network device that handles iSCSI traffic must support 9K jumbo frames. If
you are not sure that every device in your iSCSI network supports 9K jumbo frames, then do
not turn
on jumbo frames.
• Devices on both sides (server and SAN) must have jumbo frames enabled. It is recommended that any
change to the jumbo frames enabled/disabled setting is conducted during a maintenance window.
• If MTU frame is not set correctly on the data paths, then devices cannot communicate. Packets that
are larger than MTU size are discarded and do not reach the destination.
• QLogic 4010 series cards do not support jumbo frames.
Perform the following steps in the Dell Storage Manager Client to display the model number of an iSCSI
I/O card:
1. Use the Dell Storage Manager Client to connect to the Storage Center.
2. Click the Hardware tab.
3. From the Hardware tab navigation pane, click the Controllers node.
4. In the right pane, click the IO Ports tab.
5. In the iSCSI area of the IO Ports tab, the Description column displays the model numbers of the
iSCSI I/O cards.
Other iSCSI Settings
The following settings are Dell recommended iSCSI settings and best practices.
Table 24. Recommended iSCSI HBA Settings
Setting iSCSI Best Practice
Full Duplex • Use auto-negotiate for all interfaces that negotiate at full-duplex and at the
maximum speed of the connected port (1GbE or 10GbE).
• If a switch cannot correctly auto-negotiate at full-duplex or at the maximum
speed of the connection, it should be hard set at full-duplex and at the
maximum speed of the connected port (1GbE or 10GbE).
MTU Verify the optimal MTU setting for replications. The default is 1500 but sometimes
WAN circuits or VPNs create additional overhead that can cause packet
fragmentation. This fragmentation may result in iSCSI replication failure and/or
suboptimal performance. Adjust the MTU setting using the Dell Storage Manager
Client.
Switch
• Configure switch interfaces that connect directly to servers or storage systems
to forward using PortFast or Edgeport. Go to the Switch Configuration Guides
page and refer to the guide for the current switch.
• Ensure that any switches used for iSCSI are of a non-blocking design.
• When deciding which switches to use, remember that you are running iSCSI
traffic over the switch. Use only quality, managed, enterprise-class networking
equipment. It is not recommended to use SBHO (small business/home office)
class equipment outside of lab/test environments. Check the Dell Storage
Compatibility Matrix to ensure it has been fully tested to work in a SAN.
VLAN • To find best practices, go to the Switch Configuration Guides page and refer to
the guide for the current switch.
• Maintain two separate VLANs when using multipathed iSCSI.
• Disable unicast storm control on every switch that handles iSCSI traffic.
180
iSCSI Settings