2 Gigabit FC Card - How Fast is It, Really?

Common misunderstandings:

“If I buy 2 Gigabit HBAs I will get 2 Gigabytes of throughput, that’s more than enough throughput for my 400 MB/s application”

“I only need 2 disks to store my 1 TB database, now that we have 500GB disk drives are available!”

The first misunderstanding is not just about bits vs bytes, its understanding the context of when and where the [unit of measurement] bits vs bytes is used. For example, in the world of networks
(Ethernet, Fibre Channel, etc.) bits is a common unit of measurement, whereas bytes is used to describe throughput outside the network; i.e., disks or HBAs. Just be aware of the unit measurement and the context of its use.

To convert 2Gbits into Mbytes :

2Gbits = (2* 1024 * 1024 * 1024) / (1024* 1024) / 8bits
= 2147483648 / 1048576
= 2048 / 8
= 256Mbytes

The second misunderstanding has to do with sizing for capacity instead of sizing for throughput. Always size for throughput.