Fibre Channel Design 1

[kHz]

+---------------------------+
| |
| | Server
+---------------------------+
|___| |___| 2 Single Channel HBAs
| |
| |
| |
| |
+------+ +-------+
| | | |
| | | | Fibre Switches
+------+ +-------+



+---------------------------+
| |
| | Server
+---------------------------+
|___| |___| |___| |___| 2 Dual Channel HBAs
| | | |
| -----|------| |
| | | ----------|
| | | |
+------+ +-------+
| | | |
| | | | Fibre Switches
+------+ +-------+

Above are two diagrams: The first is a single server with 2 single channel HBAs, while the second is a single server with 2 dual channel HBAs. With the single channel HBAs, if a switch goes out, a server is left with one path for I/O. Using the dual channel HBAs, if a switch goes out, the server still has two paths for I/O. Also redundant in the dual channel HBA diagram is the scenario of one switch and one HBA going out simultaneously. While it doesn't leave two I/O paths, it still leaves one available path for I/O, therefore, the server remains available.

Of course I plan to have more than one server connected to fibre (who would only have one?), but I was wanting input if my diagrams seem logical and correct for the use of dual channel HBAs and two switches.

I would be grateful for any and all input. (I hope the rough line sketches generate properly.)

 

[comtec17]

Never put the 2nd channel of the same HBA down the same path and the 1st.

 

[kHz]

Yeah, the diagram didn't generate correctly.

Essentially, say I have (dual channel) HBA0, HBA1, Switch0, Switch1. So HBA0 has one channel to Switch0 and one channel to Switch1; and HBA1 has one channel to Switch0 and one channel to Switch1.

Would you agree with this? When would one use a single channel HBA?

 

[comtec17]

Absolutly. Dual Channel HBA's are for you to have more ports for your server than you have PCI slots. You never want to put the same device down HBA0 port 0 and 1 as the HBA at that point is a single point of failure.

I ported your diagram over to a different doc and you it is correct.

 

[kHz]

Thanks a lot. I appreciate it.