Weird behavior from HGST 6TB SAS drive

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rubylaser

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I just bought a used 7K6000 SAS disk to add to one of my Norco 4224 cases at home. I have (3) H310s in this case flashed to IT mode. When I install the disk, the power LED comes on but the disk never powers up or shows up in Linux.

Other SAS disks in this same slot, or on the same backplane all work fine (I tried other slots on different backplanes with the same effect). So, I assuned the disk was just DOA...

But, before RMAing it, I tried one more thing. I disconnected one of the 8087 -> 8087 cables from my H310 to the backplane and instead hooked up an 8087 -> 4x SAS cable. I supplied power from my PSU with a 4-pin molex to SATA power plugged into the back of the SAS plug. Now the disk spins up and is visible in Ubuntu?!?!

At first, I thought this disk might have the new power disable feature, but then I remembered my backplanes all use molex plugs, so that shouldn't be an issue (plus, it doesn't look like these disks have that feature).

I'm at a loss on how to get this drive working on my backplanes and hope someone has a good suggestion.

Thanks!

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pricklypunter

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I'm still thinking power disable is being invoked by your backplane, it prolly has 3v3 going to that pin with the regulation being done on the backplane itself, if that's the case, you have a little surgery to perform :)

I don't know the exact model of disk you have, but have a read through this
 

rubylaser

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Thanks for the comment ! I have a HGST 7K6000 SAS drive. I have read that off, and it doesn't mention these drives and appears to say that if I'm using a molex to SATA adapter it should be fine.

Currently, I just have a 4-pin molex from my PSU plugged directly into the backplane. I hate to even say this, but I wonder what would happen. If I did molex to SATA and back to molex into the backplane.

Edit: it does say 7K6000's do have this feature, but is says SAS disks like mine should not be effected.
 

pricklypunter

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I meant that the 5V rail is regulated down to 3v3 on the actual backplane itself. So the Molex goes to the backplane, the backplane then regulates any additional voltages as required. The surgery I'm talking about would involve removing the 3v3 on the power disable pin, easiest way would be to cut the track with a scalpel etc. Obviously, you'll want to stick a meter on that pin on the backplane connector and confirm that it has the 3v3 supply on it before tearing into it :)

Oh, third line down from the top of the doc that I linked above, mentions 7k6000 as being one of the drives with the new power disable feature ;)
 

rubylaser

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This FAQ response makes me think that SAS disks like mine aren't effected by this though.

Q: If I am using SAS HDDs, should I be concerned?

A: No. This feature is available for use on newer SAS chassis. Older SAS chassis will ignore this feature. Specifically, SAS HDDs never defined an alternate usage to P3 (Pin 3), and therefore legacy systems will have it as a “no-connect”. With SATA, the story is different. Some legacy SATA power supplies tied P1 (Pin 1), P2 (Pin 2) and P3 (Pin 3) together to 3.3V resulting in P3 (Pin 3) being permanently powered “high”, thus sending a permanent “hard reset” signal to the HDD.

Also, my PSU isn't "legacy". It's an EVGA G2 750 watt bought a little over a year ago.

I would hate to cut my backplane if this wasn't the solution. [emoji1]

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pricklypunter

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Stick 3v3 on P3 on the disk and see if it spins down. I'm betting it will, but this would confirm that. Also I'm not saying sever the track on the backplane just in case, I'm saying stick a meter on P3 and confirm if it has 3v3 on it, and if it does, then cut the track :)

The likelyhood is that the backplane was built to cover the largest range of SATA disks on the market at design time. The target market for the Rosewill/ Norco chassis was the home lab user, not necessarily the enterprise market. With that in mind, it's much more likely to find SATA disks at home and SAS in the workplace :)
 
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rubylaser

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Stick 3v3 on P3 on the disk and see if it spins down. I'm betting it will, but this would confirm that. Also I'm not saying sever the track on the backplane just in case, I'm saying stick a meter on P3 and confirm if it has 3v3 on it, and if it does, then cut the track :)

The likelyhood is that the backplane was built to cover the largest range of SATA disks on the market at design time. The target market for the Rosewill/ Norco chassis was the home lab user, not necessarily the enterprise market. With that in mind, it's much more likely to find SATA disks at home and SAS in the workplace :)
First of all, thanks for the info. Unfortunately, I have a multimeter, but I honestly don't have a clue what to do with this info. Although, I conceptually understand what you are describing, I don't know how to proceed[emoji15]

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Terry Kennedy

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A: No. This feature is available for use on newer SAS chassis. Older SAS chassis will ignore this feature. Specifically, SAS HDDs never defined an alternate usage to P3 (Pin 3), and therefore legacy systems will have it as a “no-connect”. With SATA, the story is different. Some legacy SATA power supplies tied P1 (Pin 1), P2 (Pin 2) and P3 (Pin 3) together to 3.3V resulting in P3 (Pin 3) being permanently powered “high”, thus sending a permanent “hard reset” signal to the HDD.
There are very few SAS-only backplanes out there. Most of them support SATA as well, since that's they way a lot of people use them. This is true regardless of the backplane-to-controller connector type or whether or not there is an expander on the backplane.
Also, my PSU isn't "legacy". It's an EVGA G2 750 watt bought a little over a year ago.
That FAQ is worded badly. It should say "legacy backplanes", not "legacy power supplies". A backplane that uses 4-pin Molex connectors exclusively is either regulating its own +3.3V (since the Molex connector only provides +5V and +12V) or just has pins 1-3 tied together with a pullup resistor to +5V. Most drives don't use the +3.3V pins because the standard single-drive Molex to SATA power adapter doesn't provide it.
I would hate to cut my backplane if this wasn't the solution. [emoji1]
You could also use a little piece of Kapton tape to cover that pin on the drive's connector, similarly to the way people use it to isolate the PCIe SMBUS pins B4 and B5. It may come off and stay in your backplane when you remove the drive - in that case, just go fish it out with tweezers and a flashlight.
 

pricklypunter

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I like the Kapton tape idea for a one off solution :)

Going forward, if I was going the SAS route, I would bite the bullet and mod the backplane :)
 
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rubylaser

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I like the tape idea too. I'll have to buy some Kapton as I don't have any around the house.

This is just a backup server and has almost all SATA disks in it, so the tape method will work just fine :)

Just to make sure I tape the correct pin, I would assume it's the third one in from the right on the left side of the divider.

 

T_Minus

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Kapton Tape -- I haven't heard/used that in AGES! What are you guys using it for around your house/offices/shops? Looks like something I need to "have on hand" ;) LOL!! If I recall good heat tolerance, and electrical safe/blocking/anti-static... tons of usages come to mind, just curious where you're all using it most...

Generic or 3M brand?


/end off topic ;)
 

pricklypunter

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Kapton Tape -- I haven't heard/used that in AGES! What are you guys using it for around your house/offices/shops? Looks like something I need to "have on hand" ;) LOL!! If I recall good heat tolerance, and electrical safe/blocking/anti-static... tons of usages come to mind, just curious where you're all using it most...

Generic or 3M brand?


/end off topic ;)
I use it to mask off and protect SMD components when using hot air tools and reworking boards etc. I also use it to insulate close tolerance parts, just like masking pins on edge connectors etc. Sometimes I'll use it on transformer rewinds or for providing an insulation layer along a bare metal edge or under an area of a board in an enclosure etc. It really just depends on what the requirements are, but it has lots of uses, one of my favourite uses is just simply taping down inter board wiring for example :)

3M definitely make good tapes, not the cheapest out there, but trusted and reliable, I have no plans on changing :)
 

frogtech

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@rubylaser

Not to resurrect an old-ish thread but I just picked up 12 of the same drives you mentioned in the OP, the 6TB HGST SAS disks, mine look like t hey're from an HP StoreServ 7000. I had to cover the third pin as instructed on your blog but I wonder, are all of the drives like this or is it just ones made for certain OEM's storage applications/solutions?

By the way, what is the "correct" fix for this? I have my drives plugged into an Adaptec 71605 with a standard mini SAS HD breakout cable (1 miniSAS HD to the 4 SFF 8482). Is it backplane or cable dependent? I skimmed through the thread so I'm gonna go back and read it more thoroughly now.
 

nthu9280

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I have seen two types of 8482 breakout cables.
If you are using the one with 4 pin molex power connector, you shouldn't need the tape. If it is 15 pin SATA power connector, you will most likely need to use the tape.