On Fri, 2021-06-18 at 19:36 -0300, George N. White III wrote:
The power block says its output is 3A at 12V.
The drives are both WD model WD10EZEX, (though the label on one says
it
has a 64MB cache and the other doesn't). Both labels say 5VDC, 0.68A and 12VDC, 0.55A. Looks like the dock's power should be enough.
The spec sheet < https://documents.westerndigital.com/content/dam/doc-library/en_us/assets/pu...
says 12V peak load is 2.5 A. It does take power to spin up to 7500 RPM, and I doubt your supply could survive without staggered startup.
I see. That makes sense I guess, but 30 seconds is still a very long time to wait for the first drive to reach speed before spinning up the second one. Unfortunately the data sheet says nothing about start time.
Amazon has a popular Sabrent disk-only dock -- one review notes:
Cons
- when using 2 drives and plugging or unplugging one drive BOTH
go offline, at least temporarily. NOTE: Seems to be a common
limitation
to all these docks. I have yet to find one that does not behave
this
way. Must be the way the SATA bus controller is designed.
- when plugging in 2 drives, they mount sequentially, meaning you
have to wait for one to mount before the other will
My problem is that one drive comes up almost instantly and the other takes 30 seconds. In fact I can live with that. My real gripe is that the kernel makes me wait even though the drive is not being accessed. If it just wants to make the drive available, it should be able to
wait
asynchronously.
Agreed, but then you need a way to tell the kernel that it won't need anything from the external drives so it is OK to continue booting. Have you considered automounting the drives?
They are automounted, and have been ever since I started using them. The drives are used almost exclusively for backup during the night, which is why I want them spun down most of the time and started on demand.
poc