"All cards are the same, right?"
I worked on a project a while back which had many remote sites, each with its own server cluster and a shared SCSI JBOD (OK, a long while back!). The design was all IBM and worked fine through testing. Come to ordering and the purchasing manager decided to save a few quid by replacing the IBM HBAs with some cheaper cards from Taiwan. Not surprisingly, despite the Taiwanese manufacturer's claims, they did not prove to be as reliable as the IBM hardware, and the project lost time and money as we had to keep sending engineers out to the remote sites on a regular basis to replace the cheap HBAs. Not surprisingly, the purchasing manager was let go soon after.
Biting the hand that feeds IT
