Dual Port HBA vs Single Port HBA

[Chris Gordon]

[Douglas Zhande] “1. I would like to know if dual port hba fc is faster than a single port hba , both with same same speed.”

Yes, you have twice the bandwidth to the array.

You have several ways of doing this:

1. Have an array that supports multiple paths to the same LUN simultaneously and multipathing software on the host that handles that.
2. Break your data across multiple LUNs on the array and zone different LUNs to different HBA ports. This means you need to balance what goes on which LUN yourself to get balanced/max throughput. This will look like many different disks on your host.
3. Similar to #2, but you use an LVM or something similar to stripe a filesystem across all of the LUNs present to the host.

Now think about why you want or need this. The premise would be that you need more than you can get out of a single HBA — the most you find these days are at 8Gbps. Do you really need that? Do you have an array that can handle that? How much money do you have? If you really think you need this, you are probably in a situation where you have (or should have) a Storage Administrator on staff.

[Douglas Zhande] “2. Is Qlogic adapter PCI – e 1.1 faster than PCI X 2 qlogic adapter”

Wikipedia has great descriptions of the different PCI versions and the bandwidth they provide. Combine that with the speed of the particular HBA and the more limiting component is your bottle neck.