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EonStor GSa 5000 Series Hardware Manual
2.3.3 SAS - host connections
This section details about the connections between SAS and host using SAS cables. The SAS cables (8
pairs of 28 mm AWG) are characterized by the following:
•
100 Ohms
•
Black color
•
UL-approved, lead free 50 cm, 120 cm, or 170 cm in length
•
Connectors must be secured to the receptacle of the chassis using a latching mechanism
WARNING!
The SAS cables are sensitive and must be handled with care. To prevent interference
within the rackmount, the cable routing path must be carefully planned and the cables must not be bent.
NOTE:
Contact your local vendor to purchase compatible host-link cables.
2.3.4 Ethernet - host connections
Before performing the connections between Ethernet and host, take note of the following requirements:
•
Ethernet cables are user-supplied. We recommend you to use CAT5e shielded STP type network
cables or cables with better performance types (important for meeting the requirements imposed by
emission standards).
•
Use of straight-through Ethernet cables with RJ-45 plugs.
•
Use of cross-over cables. These cables are automatically detected and rerouted for a valid
connection.
See below the list of connection types:
•
Directly to iSCSI initiators (software or hardware) or via the Gigabit Ethernet switches.
•
To servers equipped with iSCSI HBA, preferably a hardware TOE (TCP/IP Offload Engine) card,
then to client stations with an Ethernet NIC or iSCSI HBA.
•
The system presents its logical volumes via SCSI-like IDs and LUNs. These RAID volumes then
appear as iSCSI targets via the network.
IMPORTANT!
Even though the iSCSI initiator software is a cost-effective way of building an iSCSI
SAN, this software initiator adds additional workload to the server CPU. We recommend you to apply
iSCSI HBAs that come with TCP/IP offload engines in order to reduce overhead.
Network and host connection topologies
The iSCSI host ports must be connected to Ethernet network devices and iSCSI initiators that comply
with IEFT iSCSI standard (RFC 3720). The network connection of the iSCSI ports is flexible. The use of
network connecting devices, subnet, name servers, or iSCSI management software varies from case to
case.
Note that the host NIC ports and the storage system’s iSCSI host ports must be configured in the same
subnet, and the following:
•
Use the Ethernet Management port for management purposes only such as EonOne or telnet
console. This port must not be used for I/O processes.
•
Configurations such subnet or virtual LAN can separate iSCSI host links, decrease overhead, and
eliminate the impact of link failure.
•
Multiple arrays or logical partitions can be created and made available separately via different IDs
or LUNs on host ports. Usually, a RAID5 logical drive of 8 members sometimes brings optimal array
performance.
