Adding 24th drive to my SC846 makes it throw errors, card or backplane?

Joey2socks

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Dec 14, 2019
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BPN-SAS-846A - Backplane
ASR-72405 - PCM card
Supermicro - X9DRi-LN4+/X9DR3-LN4+ - Mobo
Unraid 6.6.7 - OS
25 8tb drives (one internal)

I asked in another forum but thought I’d ask here too for a second opinion.

When I add my 24th drive to my backplane I start getting a ton of errors from multiple drives in Unraid and the drives get disabled. If I add the drive internally to the MOBO through sata all is well (I have 2 mounted in there now and want to move one back to the 24th slot on my SC846)

Thought it was the cable, switched it and it still happens. Then I got another backplane (same model) and it still happened.

This made me think it was the ASR-7204 but talking to and searching around forums like this one I’m seeing conflicting views.

Some people say an 846A is fine for 8TB drives and I’ve seen comments saying People should use SAS2 backplanes with drives my size.

So I’m here because I wanted to know does this sound like a card or backplane issue? Should I buy a SAS2 backplane? Or should I replace my card with something better?

There are a decent amount of comments on backplanes but I swear finding information about my card is hard as shit.
 

pricklypunter

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If I were forced to guess, I would have to say that the Adaptec card is the likely culprit. There is a reason why lots and lots of folks use LSI cards for these things, I'll let you ponder on why :)
 

Joey2socks

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If I were forced to guess, I would have to say that the Adaptec card is the likely culprit. There is a reason why lots and lots of folks use LSI cards for these things, I'll let you ponder on why :)
Yeah I figured. Someone told me to get an LSI 8i with an HP expander. But just wondering is that the best option. I’m looking for something I don’t need to flash, preferably one card and expander if needed. There’s so many LSI cards and so many posts where people will bring up little quirks about each one. I don’t mind spending a little extra for reliability and ease of use.
 

kapone

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May 23, 2015
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If I were forced to guess, I would have to say that the Adaptec card is the likely culprit. There is a reason why lots and lots of folks use LSI cards for these things, I'll let you ponder on why :)
Well...while that may be true in this case, we can't really generalize it. I run Adaptecs almost exclusively (for various reasons) and I have had >48 drives connected to a single card (using expanders) with zero issues.

I guess, it can be considered a data point.

OP: Is it possible the card has a bad port? Move the cables around and see if the same drive fails or does the failure move with the port.
 
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Spartacus

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Well...while that may be true in this case, we can't really generalize it. I run Adaptecs almost exclusively (for various reasons) and I have had >48 drives connected to a single card (using expanders) with zero issues.

I guess, it can be considered a data point.

OP: Is it possible the card has a bad port? Move the cables around and see if the same drive fails or does the failure move with the port.
+1 swap one of the cables to another port and see if one of the existing drives goes out ~ though its low likelyhood its easy/free to check.

Edit (corrected link): Worst case scenario if it is a bad port you could grab a reverse breakout cable for one of the drive segments and feed it to sata ports https://www.amazon.com/dp/B081V8ZVD7/ref=cm_sw_em_r_mt_dp_U_oPz9DbBVJNXAK
 
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Joey2socks

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Well...while that may be true in this case, we can't really generalize it. I run Adaptecs almost exclusively (for various reasons) and I have had >48 drives connected to a single card (using expanders) with zero issues.

I guess, it can be considered a data point.

OP: Is it possible the card has a bad port? Move the cables around and see if the same drive fails or does the failure move with the port.
You and @Spartacus make good points.

A question though. I’ve been hesitant to test it since whenever I test it it basically destroys my Unraid parity, all the errors and disabled disks and having to rerun a parity check. Last time I had 100K errors that had to be corrected.

I might have to ask this on the Unraid forum but all those errors in testing does it do anything to the drive or are they just read errors and the drives are fine?

also I might as well ask you guys since I’ve never really asked but been kind of scared. I buy used cards on eBay, is there anything I should do before attaching them to my drives? Sorry if I’m a bit green on this I just made the switch to enterprise gear last year and it’s been a fun confusing ride.
 

kapone

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May 23, 2015
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Assuming you're not actively writing to this pool (and you shouldn't be, until you figure this out), yes, those should all be read errors. They should not be destructive at all.

It's the equivalent of pulling out disks from a RAID array, and the array fails because...well..umm..disks aint there. :) But the moment you plug them back in, the array is somewhat happy that it can now read all disks, but it's not gonna be happy as a clam until it has run a consistency check. That's the same thing that Unraid is doing, just in software.

Buying used cards is...not ok? Shit, nobody told me! :) As long as they work, and are not intended for some sort of critical, production activity that requires active support from the vendor, buying used is gospel around here.
 
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Spartacus

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I use unraid, and I've bumped one of my controller cards out of the slot more times than I can count due to it's position.
If its more than a couple of drives missing it wont start the array no harm no foul.
For one disk I think it'll start but not like it is missing a disk, worst case it would cause one of the parity disks to rebuild if data is written after start to when you get the missing drive reconnected.

Edit: that said you could set the array to not auto start and verify whether the disk shows once unraid boots then go from there with no risk.
 
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i386

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Some people say an 846A is fine for 8TB drives and I’ve seen comments saying People should use SAS2 backplanes with drives my size.
The 846 A & TQ chassis have a "passive" backplane; all signals from/to the hdd/ssds go through the backplane to the hba/raid controller without interfering. They have the speed and drive size limitations of the controller.
 
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Joey2socks

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Buying used cards is...not ok? Shit, nobody told me! :) As long as they work, and are not intended for some sort of critical, production activity that requires active support from the vendor, buying used is gospel around here.
Thanks for all the info!

Yeah I like the used market, holy crap so much cheaper than when I used consumer gear!

I know it might be dumb but I sometimes think “what if the last guy kept some hardware raid or some weird setting that will wipe my drives when I spin up!!!” Irrational and I’ve literally never heard of this but because enterprise is newish to me I get weird.
 

Joey2socks

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The 846 A & TQ chassis have a "passive" backplane; all signals from/to the hdd/ssds go through the backplane to the hba/raid controller without interfering. They have the speed and drive size limitations of the controller.
Thanks. I would see some posts talking about A’s and TQs. There’s one that says you need SAS2 board and others that didn’t. Just wanted to make sure which was right.
 

kapone

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Thanks for all the info!

Yeah I like the used market, holy crap so much cheaper than when I used consumer gear!

I know it might be dumb but I sometimes think “what if the last guy kept some hardware raid or some weird setting that will wipe my drives when I spin up!!!” Irrational and I’ve literally never heard of this but because enterprise is newish to me I get weird.
For almost ALL hardware raid cards, the settings for the RAID array are in the array, not in the card. That's why you can move arrays between cards and everything works the way it is supposed to. There might be scheduled scan settings etc that are on the card, but they will never be destructive.

p.s. You don't do do a "factory reset/default settings" when buying used stuff and installing it? Umm... ;)
 

Joey2socks

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Dec 14, 2019
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Joey2socks

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Dec 14, 2019
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Just updating this in case anyone ever does a google search for the same problem

Solved: Bad Port

I googled which port controls which slots, its in the pdf manual, and started moving cables around like @kapone said and the errors started on the new group of drives. I am using the cable @Spartacus told me to use and its working perfectly. Now its off to replace my card with a different one.