On the rare occasions I need to restart one on my servers it starts with missing HDDs, there are 10 HDDs, some 8TB some 3TB, I start the system and a few HDDs are missing so the array doesn't start, so I restart the system and a different set of HDDs are missing, sometimes its just one HDD and sometimes its five HDDs and always different HDDs.

I tried one rail from the PSU to drive all 10 HDDs and two rails to drive five HDDs each but it still does the same.

I had two controllers running four HDDs each with the rest running from the motherboard SATA controller and it still did the same, so I bought a 24 SATA controller but its still the same.

After a few restarts it works fine, then the other day it just stopped, it had never just stopped before, I restarted the system and it came back with a corrupted USB stick.

I turned it off to sort out later, when I got around to sorting it out, I restarted and it was back to random missing drives again and no corrupted USB stick.

After a few restarts it is now back to running normally again.

Where do I start to fix my problem? is it just a dodgy USB stick?

4 hours ago, phileeny said:

I tried one rail from the PSU to drive all 10 HDDs and two rails to drive five HDDs each but it still does the same.

If you have any power splitters in use, those can definitely cause these kinds of strange issues.

 

So can a weak PSU that is on the edge of just enough power, but not fully failed yet.

PSU is Corsair CX500M 500W, splitters yes x2 1 to 5 SATA

1 hour ago, phileeny said:

PSU is Corsair CX500M 500W, splitters yes x2 1 to 5 SATA

Is that splitter a molex->SATA or a SATA->sata?    If the latter then that will definitely be a problem, 

Sata to Sata like this 

Yeah, that is NOT going to work well for spinner drives. It's questionable for SSD's, and not nearly enough power for HDD's.

 

There is a very good chance whatever connector you have been feeding them from, as well as the source end of the adapter, have heat damage from overcurrent.

 

You need the beefy 4 pin molex type connector feeding that many drives.

So if I get a molex to 4 sata cable "beefy" as you say, and I would need three, would I connect all three to the same rail?

also, any recommendations of a "beefy" cable.

Here is an example of a well constructed cable.

https://www.amazon.com/dp/B009GULFJ0/

Here is an image of what to look for, generally.

Notice the clear separations with distinct compartments for each cable. Avoid molded ends, the manufacturing process is so sloppy there have been many reports of fires caused by direct shorts inside the molded end, typically after the cable has been in use and experienced some normal heating cycles.

 

The molex 4 pin end is not normally subject to this type of failure, as the wires have much greater separation.

 

10 hours ago, phileeny said:

would I connect all three to the same rail?

I do not think that word means what you think it means.

 

Very few power supplies split their rails across connectors of the same type. Normally all the drive power connectors, SATA and 4 pin, will all be on the same rail, regardless of how many different strings of wires start at the PSU. But yes, if possible it's best to put each splitter on a separate wire set coming from the PSU. The goal is to limit the number of drives powered by any single set of wires. Each wire can only pass so much power before it starts to partially block the voltage, causing the drives to starve for power. SATA to SATA splitters are especially bad for this, as the tiny wires (comparatively) have much more resistance than the big fat wires and connectors in the 4 pin style.

Thanks I knew about the dodgy connectors, I will have a look at getting new cables to see if this solves my issue and get back to you.

 

Its been a while, so just a quick update.

I was going to buy some new 1x4 cables as per the suggestion then I remembered I had some older 1x4 cables I could try, and it turned out I had three of the Silverstone SST-CP06 power cables, these have two high quality 2200µF capacitors included on the cable to provide stable voltage to all connected devices, so I removed the two 1x5 sata power cables and fitted these, and for now all drives started first time.