Mac mini – External DASD connection lost

[InquiringMac]

Dear forum members:

I am monumentally sorry to bug you, but I do need your help badly indeed! To the best of my ability, let me describe the situation for you.

Setup

TowerRAID DASD (http://www.sansdigital.com/towerraid/tr5utb.html) is equipped with 5 Western Digital 2 TB 7200 RPM HDDs operating in JBOD mode.

TowerRAID is directly connected via USB2.0 to Mac mini working under Mac OS X 10.8.6.

All HDDs in my system are Mac OS Extended (Journaled) formatted.

Problem

While using TowerRAID to Read/Write large amounts of data (0.3TB - 1TB usually), connection is almost always (in 90% of the cases, I would say) lost during the process.

Connection is always lost if TowerRAID, while idling, is left connected to Mac mini for more than 5 - 6 minutes.

Error message I always get:
“The disk was not ejected properly. If possible, always eject a disk before unplugging it or turning it off.
To eject a disk, select it in the Finder and choose File > Eject. The next time you connect the disk, Mac OS X will attempt to repair any damage to the information on the disk.”

Note

External USB HDDs always working (during Read/Write/Idling) without any problems in my setup: Western Digital My Book Essential and Seagate FreeAgent.

Please, please help me at your earliest opportunity!

 

[waw74]

have you tried a new USB cable or switching to a different port on your mini.

i've got the exact same RAID box, and haven't had any problems. Running USB3 and RAID5 on a linux box though.
I've tried esata, but it will randomly drop off once every week or 2, i attributed that more to the computer than the RAID, but i could be wrong.
(actually i lied, just realized i have the "+b" not the "-b" so it's got USB3)

how old is your RAID box?

 

[InquiringMac]

A few additional points…

Thank you very kindly waw74!

When the connection is dropped, all TowerRAID LEDs stay solid green.

My TowerRAID box and USB cable work just fine on Windows 7 machine.

Changing USB cable and/or switching to a different port on Mac mini makes no difference.

 

[InquiringMac]

Anybody?

Any suggestions would be appreciated greatly!

 

[nkawal]

I am having the same issues with a similar setup. I have a OWC Mercury Elite Pro QX2. I have 4 drives in a RAID 5 setup. I have it connected to via a Thunderbolt cable to eSATA and it gives me the same error messages and i too have green connectivity lights. I have to manually reboot drive enclosure and and re-enables connection for PLEX to work again.

 

[InquiringMac]

Unfortunately enough…

The above note means I am not alone in this conundrum, unfortunately enough…

Being new to the Mac ecosystem, I am wondering if there is something in the OS settings I am missing or misusing in any way…

Please chime in and help us!