So, I purchased a nice Micron 9300 Pro 15.36 TB U.2 drive and a Syba U.2 (SFF-8639) NVMe PCIe to Mini SAS (SFF-8643) cable to connect it to my X299 FTW K.

Unfortunately, the computer turns on, then immediately (within 1 second) turns off - and repeats that cycle until I kill the power.

I've tried both U.2 ports (both enabled in the BIOS) to no avail. I'm getting the cable replaced now, just waiting on shipping.

Anyone have any experience with these U.2 drives? Is it likely a cable problem, the drive itself, or maybe my motherboard?

Thanks for the heads up. I've gone ahead and purchased a different model U.2 cable just in case.
 
I don't have any other U.2 capable system to test with, so I may end up either trying a PCIE U.2 card, or just sending back the drive and writing off U.2 if the replacement cables don't work.

ZoranC
You are welcome! Here are my thoughts:
 
1. I have no reason to suspect port on your mb is bad. Keep in mind though to double check documentation for your BIOS if you need to do something to make it work. For example, on my X299 Dark I had to enable PU2 to make it work, and PU1 is either disabled or one of M.2 slots is disabled.
 
2. You have purchased enterprise drive. I don't know do they require some special sauce to work or they will work fine with consumer setup.
 
3. Double check that you have connected power into your U.2 cable and connection is firm. These things require separately provided power and cable too easily slips out.

Hold up - for #3, you have to connect SATA power? The U.2 standard doesn't provide all power from the PCIE lanes? If it is indeed required, apparently I greatly misunderstood what I read about U.2.

Thank you. I'll see if I can secure the connections via Velcro cable ties, as my case does make SATA/power cables bend to fit the side cover on. Well, when the RMA cable or the new one that I ordered comes in 

arestavo
Thank you. I'll see if I can secure the connections via Velcro cable ties, as my case does make SATA/power cables bend to fit the side cover on. Well, when the RMA cable or the new one that I ordered comes in 

You are welcome :) In my case zip ties FTW LOL This is the cable I got New Amphenol RHS36-2582 U.2 SFF-8639 to Mini-SAS SFF-8643 cable US-SameDayShip | eBay
 
Like I said, I found not all cables are same and, like DEJ915 said, "Amphenol" ones are good.

Zapper_Weisman
This is the one I bought: https://www.amazon.com/gp..._s00?ie=UTF8&psc=1

 
Linky no worky :)

arestavo
Round two ended in failure as well. The Newegg seller didn't RMA the cable, just partially refunded. Thankfully I bought a second cable (non-amphenol) that came in yesterday.
 
At first the drive wasn't seen - so I reseated the connection, which froze windows (guess U.2 isn't hot swappable after all?). After the restart it was there! Formatted and started copying 6TB over. Then it failed copying 2TB in, but the drive was still visible. I reformatted, which failed until I restarted and was then able to format it. Then the drive went missing immediately after format. 
 
I swapped U.2 ports (I was in #2, swapped to #1) and reseated the cable again and the drive is still missing. 
 
I've got an amphenol U.2 cable incoming, but at this point I think that I'm just going to return this drive as this isn't worth the effort for a technology this flaky.

I'm sorry to hear you are having hard times with your U.2 setup however I disagree with you that technology is flaky. It works fine as long as one has components that meet specs and are meant to work with each other.
 
However what you have on your hands are:
 
1. Cables that are of unknown quality and origin. To be fair one should notice that if you get USB, SATA, whichever ... cables from unknown vendors they too can end up not working reliably.
 
2. Enterprise drive that might not be guaranteed to work in consumer setup. I know at least one poster said it works fine for him but when it comes to parts that are meant to be used in servers there can be a gotcha we are not aware of, especially if we don't know where reseller got it from and/or it was used pulled from somewhere.
 
I understand why this is very frustrating on you but if I were you I would wait for that Amphenol cable and only then form your opinion.

Ok, I've finally got an amphenol cable (two overnighted because the first still isn't here two weeks later) - and it did the same thing as the prior cable (drive dropped out while copying data over).
 
At this point I don't know what to do other than return the drive.

ZoranC
 
I am very sorry to hear you are still having problems. At this point in time I too would be suspecting a drive, especially if you got exactly ones from that exact seller in eBay link you posted. I have two of those and both have been working fine for months.
 
Unfortunately only way to confirm your drive is one causing the issue would be by testing those cables with consumer level U.2 drive that is known to work fine. So I guess you will have to decide how to proceed while keeping in mind return period for your drive.
 
P.S. Are there any errors in Windows event logs when this happens? I assume you checked drive firmware is up to date (assuming once can update it) and if there are any Micron’s drivers for it?

Yes, 3 of them with 1 lost in the mail.
 
It's got the latest firmware - that's the one thing that I did right off this time is install Micron's Storage Executive software to check it & used it to install the driver. I wasn't able to find anything in the event logs, but I've been known to not see stuff (literally) in front of me - it's a talent?
 
I don't have any other drives to test it with - but I'm going for a last hoorah. I installed the second amphenol cable in the top U.2 slot (IIRC that's #2, the first cable I tried in the bottom connector), cranked down my cable management ties FIRMLY sandwiching the cable and the drive, hooked into a different SATA power cable, and removed the drive from the 3.5" bay caddy and now have it sitting on some cables right in front of my four 180mm fans (very ghetto, I know - but they are very short U.2 cables). The drive is back to being seen and the temps are down to 32C from 42C while copying - now let's see if the 6TB copy fails out again.

ZoranC

arestavo
I wasn't able to find anything in the event logs, but I've been known to not see stuff (literally) in front of me - it's a talent?

FWIW Windows event logs tend to be very overwhelming (yet often not verbose enough). Filtering on ‘error’ and ‘critical’ combined with filter on time window helps me when I need to tame.
 

arestavo
I installed the second amphenol cable in the top U.2 slot (IIRC that's #2, the first cable I tried in the bottom connector), …

According to my drawings tip U.2 slot is PU1, bottom is PU2. It is my understanding PU2 is one people have problems with when using lesser quality cables. My cable is in PU2. Be warned that having drive in PM1 disables PU1, you can’t have both.
 

arestavo
… now let's see if the 6TB copy fails out again.

Do you have problems only when trying to copy 6TB? What are you using to do copy?

Thanks for the tips with for the event viewer. 
 
Yes, with the previous cable and the first amphenol in connector 2. Just copying over my steam directory from my RAID array - the first time it failed out ~2TB in, the first amphenol cable in connector 2 failed out ~60GB in. Currently it's 2.2TB in with the second cable in the first connector... so maybe those changes worked?

@arestavo How did it go?

arestavo
Just woke up (late night) - and a complete copy of all 9TB of my games was successful!
 
I'm not sure what fixed it, but it was one of the last ditch efforts (maybe using the top U.2 connection, maybe the swapped power cable, maybe the extra tight cable straps holding the cable to the drive, maybe the lower temps - maybe all of them).

That is great news! Considering everything that was going on I would now, if I were you, do -full content- compare between RAID and U.2 twice (once with WinMerge and once with Beyond Compare) and if both check out than you are most likely good.