Drobopro connected via Firewire 800 is knocked offline during file transfer

Hello all, I’m hoping there’s a simple solution to this odd problem.

I recently migrated my drobopro from a gig iscsi connection to a firewire 800 connection. I notice significantly greater throughput to the storage however during file copy the drobo is knocked offline and then minutes later it re-initializes and comes back online.

I have the storage shared out using Windows7 and have changed the necessary registry keys to enable file server mode.

"allocate resources accordingly. Set the following registry key to ‘1’:
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management\LargeSystemCache

and set the following registry key to ‘3’:

I even tried both enabling and disabling SMB2 functionality, notably with it enabled the file transfers speeds quickly degrade.

I’m using the UBCore v5.72 drivers from Unibrain which appear to be the only drivers that allow my card to see the drobo’s drives.

Has anyone else experienced this strange behavior?

Another discovery this morning… when attempting to copy a large file 25+GB from one location on the drobo to another (the same lun) the transfer starts fast then immediately comes to a crawl, I then observe the same problem where the drobopro drops offline as observed in the drobodashboard…

I’m wondering if I have a faulty 1394b card or is there something else at play here?

I recommend submitting a support ticket describing your problem and including the diagnostic log. There might be some correctable-but-annoying issue that’s causing the hiccups.


Thanks for your suggestion, I called drobo support, submitted my diagnostics report and determined a few things…

  1. I need to switch back to iscsi since it’s supposed to be 3x faster.
  2. My storage is over 88% utilized and the drobo’s i/o performance is reported to decrease at 70% or higher.

I’m adding more storage tomorrow and have switched back to iscsi. Hopefully this helps.


Still strikes me as strange though - it shouldn’t completely disappear from view.

Makes me feel like there might be some data-transfer contention - for example, a burst of data “overloads” the bus and it pauses to catch up or something.

After switching back to iSCSI you may want to reset the TCP/IP networking stack. My Win 7 machine slowed to a crawl, then I reset the stack and it was spiffy again. Not sure what the root cause of my slowdown (or yours) is though.