I find this “explanation” absolutely retarded (I’m not directing this at you personally, bhiga). I have, of course, seen this mentioned several times during my troubleshooting. Why should I have to jump through all these hardware configuration hoops in order to get even halfway decent speeds out of my Drobo? The speeds I posted above can in no way be explained by having a Firewire 400 device on the bus and having the bus operating at 400 Mb. In fact, you can see the peaks of my speeds are pretty much equal to what bhiga achieves. The peak write is about 38 MB/s and the peak read is about 53 MB/s (which exceeds FW400 bandwidth). It’s just the constant, non-stop drops to sub-10 MB/s make the overall performance horrendous.
Here are the results of a Firewire 800 external hard drive that I have connected to the Mac at the same time as the Drobo! Note, I’ve never had to do numerous firmware updates or other cable, power supply, or device voodoo to this hard drive to get decent performance out of it. I’ve never had to question whether my firewire bus is defective or if another device is making it slow. I just plug it into my Firewire 800 bus, and it works fast, regardless of any other devices that are plugged in. That’s what I would expect from my Drobo too.
But, just to humor everyone, I’m disconnecting EVERY firewire cable from my Mac except my Drobo. (That is, I’m disconnecting the FW800 drive above, and disconnecting the FW400 cable that goes to my Cinema Display hub (no devices attached)). Here are the results:
Ooh, yeah, we’re doing awesome tonight. I believe what AJA is telling me too, because tonight, I tried to copied a 5.52 GB DMG file from my Drobo to a USB drive. Took 26 minutes.
And here’s what the firewire bus looks like for that test, just to confirm nothing else is hooked up: