Difficulty keeping 20+ USB Block Eruptors stable

[mccminer]

I don't know how these guys with 100's of Block Eruptors do it.  I'm trying to run 32 of them off of one Ubuntu 12.10 box running BFGMiner 3.1.4 right now, no matter what I try, I can't seem to get them all to work stable together.  I'm using D-Link DUB-H7 powered USB hubs, and it's kicking my ass.  Anyone got suggestions? Ideas?

Some just don't hash at all when in the big group, but do fine in individual testing.  It's not contained to certain ports either.  The problem just moves around the more I mess with it.   

[speciall]

How many sticks per hub do you connect?

hundereds of sticks on one computer is impossible I think, is USB not lilited to 128 devices per computer?

[murraypaul]

Sounds like they could be overheating. Have you tried pointing more fans at them, see if that increases stability?

[mccminer]

I don't think overheating is an issue.  They sit right in front of a large fan and right under an AC vent.

[ypsylon]

Well from my personal experience.

Don't even try to cram 7 BE into 7 port USB 2.0 hub. It will never work (worst case scenario - it will burn hub/usb port on motherboard or USB card). It happened to me once when I plugged 7 into 7 [active] port hub and it fragged NEC USB card. Tested few and 5 is max for stable work with USB 2.0 hub. With 7 I've burned pci usb controller, but before it fried 2 out of 7 returned always 100% HW errors.

Of course cooling is a factor. Hot chips usually bang too many HW errors. Nothing fancy slow fan will do just moving hot air.

Best way with plethora BE is with really big USB 3.0 connected active hub. It will support much more hardware and power shouldn't be an issue. I went with Manhattan MondoHub [161718]. Pricey, but hey - 28 ports 4x3.0 and 24xUSB 2.0. Practically usable 2x USB 3.0 and 18x 2.0 (obscured side ports, too bad that BE boards are so wide). I will test at later date if it will detect BE properly when plugged into obscured port with extender.

My small, temporary station, not completed yet. For now connected to main PC [W7 64/BFG 3.1.3].

http://s22.postimg.org/if8au5h9d/DSCN8799.jpg

There is for certain one picture somewhere showing 30+ BE working without problem. My guess in your case - insufficient power. Ditch USB 2.0 hubs and try couple USB 3.0 - the only way to supply stable power to so many BE sticks.

[Trongersoll]

check this thread to learn more than your ever wanted to know about HUBs: https://bitcointalk.org/index.php?topic=253749.0

the table tells you how many erupters work in each one.

the 127 hard limit on USB is per controller. Depends on how many USB Controllers your MB has. PCI cards can be bought with their own controllers to add capacity.

I'm running 24 on 3 10-port HUBs with no problems.

[os2sam]

I have had great results with CGMiner 3.3.1 using direct USB.  CGMiner 3.3.2 was just released and that seems to work well to, so far and resolves the problems that some were having.

Of course I have only 15 of them.

[mccminer]

check this thread to learn more than your ever wanted to know about HUBs: https://bitcointalk.org/index.php?topic=253749.0

the table tells you how many erupters work in each one.

the 127 hard limit on USB is per controller. Depends on how many USB Controllers your MB has. PCI cards can be bought with their own controllers to add capacity.

I'm running 24 on 3 10-port HUBs with no problems.

Thanks for the link Trongersoll!  After reading, I reconfigured my set-up using only 6 ports per hub and I'm having much better success!

[astutiumRob]

I'm trying to run 32 of them off of one Ubuntu 12.10 box running BFGMiner 3.1.4 right now, no matter what I try, I can't seem to get them all to work stable together

How much power is the hub able to supply the ports (this is the main problem people have with USB BE's - Also remember most hubs are cheap-cr@p

The majority of 7 port hubs are 2x4port units in one case (with port 4 on unit1 supplying unit2) and only the 1st 3 ports can be correctly used by a lot of drivers/os

[mccminer]

Well after reading over the thread on USB Hubs, and doing my own math, I realized that even though it was a 7 port hub that I was using, the powersuply would only support 6 per hub.  I went through my setup and removed one from each hub, so that I'm only running 6 in each now.  That did the trick!  Now I have 52 of them running perfectly for a combined hash rate of 17Gh/s.