odd issue—not exactly a problem—with mounting hard drives

[wfriedwald]

it's just a mystery, why hard drives only work in certain bays / enclosures.

I have a new-ish 18TB hard drive (okay, maybe 2024).

and a new-ish 8-drive hard drive bay / rack.

for some reason, this 18TB drive does not work in this reasonably new rack.

But it does work in an older individual enclosure / device.

I guess it's not the worst problem, since the drive does work in certain enclosures, so I shouldn't complain.

(and this happens all the time, I kind of expect it with older drives, they can be finicky about where they work and don't work, you have to try a drive in several different bays / enclosures etc.)

So I am just wondering if anybody has any insight on this? Very curious.

thanks, as always, for feedback,

W

 

[Bigwaff]

for some reason, this 18TB drive does not work in this reasonably new rack.

“Does not work” means what exactly? Be specific. Does not power up? Does not mount but is visible as an attached device? What exactly “does not work”?

 

[wfriedwald]

ah! yes. it does not mount. and it does not show up as unmounted in DISK UTILITY either.

w

 

[Bigwaff]

Does your rack support drives of such high capacity?

 

[wfriedwald]

yes, I have another 18TB drive of about the same vintage already in there. So yes.

w

 

[Mrbobb]

Something is wrong, I would consult with the enclosure people, if you don't have to call China, sounds squarely like firmware can't handle multiple high-caps, maybe.

Oh, I have a 4-bay enclosure and it came with a just-strong-enough power supply, when I added drives I made sure to upgrade it with a stronger PSU so I won't have power sags.

 

[DavidPS]

Since it doesn't even appear in Disk Utility as an unmounted device, this isn't a filesystem or partition problem — the drive is never enumerating on the bus at all, so the enclosure is the place to look. Three things cause that pattern most often. First is power: a 18TB helium drive draws a big spike on spin-up, and an 8-bay unit with a marginal PSU will happily run seven drives and then fail to spin the eighth. Try the drive alone in the rack with every other bay empty — if it shows up then, it's a power budget issue, not a compatibility one. Second is the bridge chipset's per-port handling; some racks map each bay through a port multiplier and one port can be flaky even when the others are fine, so swap the drive into a bay you know works and see if the fault follows the drive or stays with the bay. Third is drive-side: check whether this particular unit is SMR or has a different sector/format setup than the 18TB you already have in there. Also worth checking the SATA power connector seating and the drive's own firmware revision against the other one — same capacity and vintage doesn't mean the same platform. If it turns out to be power, upgrading the PSU is usually cheaper than replacing the rack.

 

[wfriedwald]

thanks for the feedback!

Is there a guide somewhere on how to upgrade the PSU (power supply unit?) on a drive bay / rack?

w

PS: this is the unit (drive bay / enclosure x 8) purchased from amazon in Feb 2025:

IO CREST Hard Drive Enclosure Supports Multi Bay via USB Interface, Black, 8-Bay

Syba Sy-Enc50119 8 Bay 2.5" And 3.5" Usb3.0 Sata External Enclosure Is A Quick And Simple Way To Expand Storage Capacity. Latest Controller And Firmware Support 8 X 24TB Drives. Unique Independent Switch Design Allows Drives To Be Powered Off Individually, Prolonging The Life Of The Drives.Sy-Enc...

www.amazon.com

 

[DavidPS]

There's no PSU-swap guide for that enclosure. It's the Syba SY-ENC50119, and the official manual lists a 200W internal supply (Syba's store page sometimes says 130W — check the label on the brick itself). The PSU fan is a small 1U industrial unit, not a standard ATX supply you drop in, and the manual never describes replacing it.
Before you open the case, use the per-bay switches. Power the enclosure on, then switch every bay off except the 18TB. If it then shows up in Disk Utility, the brick is just sagging when too many helium drives spin at once, and those switches are the real fix. If it still never enumerates even alone, swapping the PSU probably will not help — that pattern is usually a dead bay/port or the ASMedia ASM1074 + ASM1153E USB bridge, not watts.
If you do open it, you'd be matching a 1U brick's rails and connectors by eye. There is no published pinout or drop-in part. Not worth it unless you already know that hardware. Cheaper path is a firmware check on Syba's product page, or a different enclosure if the drive never shows up even by itself.