Dot Hill Systems II 200 FC Manuale Utente

Pagina di 210
Chapter 4 Connecting Your Array
4-11
4.5
Cabling to Expansion Units
The instructions in this section apply to the SANnet II 200 FC and the SANnet II 200 
SATA arrays only. The SANnet II 200 SATA SE array does not support expansion 
units.
Caution – 
When connecting expansion units to a RAID array, always connect channel 
2 of the RAID array to the A channel of the expansion units, and connect channel 3 of 
the RAID array to the B channel of the expansion units. Otherwise, unexpected 
behavior might occur.
Several cabling configurations are possible, each with its own advantages and 
disadvantages. Refer to the SANnet II 200 FC and SATA Array Best Practices Manual 
for more information about the suitability of various configurations for various 
application requirements, as well as for information about high-capacity 
configurations.
The maximum number of expansion units attached to a RAID array are:
up to eight SANnet II 200 FC expansion units attached to a SANnet II 200 FC array
up to five SANnet II 200 SATA expansion units attached to a SANnet II 200 SATA 
array
up to five SANnet II 200 FC expansion units and SANnet II 200 SATA expansion 
units, in any combination, attached to a SANnet II 200 FC array
These configurations are described in the SANnet II 200 FC and SATA Array Best 
Practices Manual.
The examples in Figure 4-7 and Figure 4-8 show RAID arrays connected to two 
expansion units. Connections to expansion units are designed to keep all A drive ports 
on the same loop and all B drive ports on the same loop. 
Caution – 
To avoid drive assignment conflicts, make sure that each connected array 
and expansion unit uses a different loop ID, as described in  “Setting Loop IDs on 
Expansion Units” on page 4-13.
In the RAID array, two of the unused SFP host ports can be used to provide redundant 
pathing to the two servers, and the remaining unused SFP host ports can be connected 
to two more servers in a redundant configuration. 
Similarly, you can connect expansion units to other channels (which are separate from 
channels 2 and 3) if you configure them as drive channels. For details, refer to the 
SANnet II Family RAID Firmware User’s Guide.