Iscsi Data Path Requirements - Hitachi G200 User Manual

With Fibre Channel connections, no special settings are required for the
storage system.
Direct connections up to 10 km with single-mode longwave Fibre Channel
interface cables are supported. Link speed determines the maximum distance
you can transfer data and still achieve good performance. The following table
shows maximum distances at which performance is maintained per link
speed, over single-mode longwave Fibre Channel.
Link speed
1 Gbps
2 Gbps
4 Gbps
8 Gbps
16 Gbps
Hitachi Data Systems customer support can provide the latest information
about the availability of serial-channel TrueCopy connections.

iSCSI data path requirements

For iSCSI data paths, direct, switch, and extender connections are supported.
The following table describes the considerations for ports and network
settings when you configure a system using iSCSI data paths.
Ports
Hitachi TrueCopy® User Guide for Hitachi Virtual Storage Platform Gx00 and Fx00 Models
10 km
6 km
3 km
2 km
1 km
Item
• When the parameter settings for an iSCSI port are
changed, the iSCSI connection is disconnected temporarily
and then reconnected. Change parameter settings only
when the I/O load is low to avoid impact to the system.
• Although a log might be output in the host if you change
the settings of an iSCSI port connected to a host, this does
not indicate a failure. In a system that monitors system
logs, an alert might be issued. When this happens, change
the iSCSI port setting, and then check if the host is
reconnected.
• Delayed ACK: When you use iSCSI for the connection
between storage systems, and the same port for the
connection to the host, disable the Delayed ACK setting for
the port (in the Edit Ports window set Delayed ACK to
Disable, default = Enable).
If Delayed ACK is set to Enable, it might take time for the
host to recognize a volume used by TC pairs. For example,
it takes up to 8 minutes for the host to recognize 2,048
volumes.
• Selective ACK: Make sure Selective ACK is enabled for
iSCSI ports. Selective ACK is set to Enable by default (Edit
Ports window). Do not change this setting.
Planning for TrueCopy
Distance maximum performance maintained
Considerations
3-27