[geeks] external drive bay issues...

[Charles Shannon Hendrix]

I bought a Mediasonic 4-bay JBOD array awhile back. It worked fine on a
Windows machine and a NAS box, though it only had a single drive in it.

I retired my Mac Pro and so I put it on my new iMac with 4 drives:

- 1 SSD
- 1 4TB Seagate
- 2 3TB HGST NAS drives in, AppleRAID mirrors

The unit works fine, except when the computer goes to sleep. Upon waking,
there is a high chance that the drives disappear.

A couple of times, I have had drives disappear randomly.

It seems like every time this happened, the Seagate drivebs LED would be
flashing continuously, while the other drives were silent. I tested the
Seagate and it passes everything, SMART looks OK, and it had been running in
an Insignia case for months.

So I read a lot about the issue, and some people say the fault lies with
macOS. Several people have pointed at Applebs more aggressive hibernation
code which hibernates the machine after a sleep period has passed. This
evidently attempts to shut down USB and Thunderbolt chipsets because they draw
a lot of power.


So I used pmset to extend the sleep period to 24-hours, making it unlikely the
machine would hibernate.

That seemed to fix the problem for some time, but this morning when I got up I
got four messages about drives being ejected improperly. Looking at the unit
the mirror and the SSD were missing and the Seagatebs LED was flashing
continuously.

Sob& Ibm trying to figure out what the problem is. If this is a general
macOS issue, that sucks because it has been an issue since Mavericks was
released.

The fact that the Seagatebs drive bay is flashing every time this happens,
does make me suspicious of that drive. Maybe it has some firmware issues and
canbt run in that JBOD, I donbt know. Having said that, I read in a couple
of places that doesnbt mean anything, its just that some drives get hung in
a read loop when a USB or Thunderbolt controller fails.

I donbt really know much about the Mediasonic. It uses a fairly bog-standard
JMicron USB/SATA controller and doesnbt have any kind of software. It has a
switch that controls how it reacts to the computer going to sleep, and putting
it on b
never sleepb
 doesnbt help the issue.

Anyway, I thought I would post my observations here for commentary and
suggestions.

I sent a question to OWC about it, asking them if they were aware of issues
like that with their own external units, because it wouldnbt do me any good
to replace the Mediasonic if their own units are having the issue. Webll see
what they say about it.




--
"Where some they sell their dreams for small desires."