SAS disks

[Octopuss]

I would say the seller is legit. They communicate nicely and have a ton of positive feedback.

*LOT OF 5* HGST/HITACHI 4TB 7.2K 12Gb/s 3.5" AF SAS HUS726040AL4210 W/ TRAY | eBay

Find many great new & used options and get the best deals for *LOT OF 5* HGST/HITACHI 4TB 7.2K 12Gb/s 3.5" AF SAS HUS726040AL4210 W/ TRAY at the best online prices at eBay! Free shipping for many products!

www.ebay.com

Yes I'm sure it's SAS :)

Basic google search doesn't indicate 4kn disks being problematic with ZFS... I think I'll go for it.

 

[Octopuss]

BTW - I'm not familiar with the Fractal Node cases, but I'm under the impression it doesn't have a SAS capable backplane. What are you planning to do for cabling? SAS drives do not have the "notch" between the power and data plugs.

I'd just buy a new SAS cable I guess? Th one that will result in spagetti inside the case, with power connector sticking out of every one of the four cables :D
Like this:

 

[jgreco]

Yes, that should work.

 

[Ericloewe]

Key disclosure... "4kn"... Those are 4096 byte sector drives. Not the usual 512 byte.... That's one of those new standards that hasn't been entirely well received... You need to research how ZFS handles those.

Easily, just don't throw them into an existing pool that's ashift=9.

 

[Octopuss]

I saw that parameter come up in several google searches.
What exactly is that?

 

[Ericloewe]

The ashift is effectively the minimum block size, nominally as dictated by the disks’ allocation unit (historically 512 bytes, and 2^9=512).
TrueNAS defaults to ashift=12 (2^12=4k) to account for the likely future use of disks that do not present 512-byte sectors (note that basically all disks use 4K sectors internally these days anyway).

 

[rvassar]

I saw that parameter come up in several google searches.
What exactly is that?

I think... (#include std_disclaimer.h) it's a parameter that ZFS uses to set alignment at vdev import. I don't believe it has ongoing operational impact after that, but I'm not sure. It might affect how ZFS handles unaligned writes, or have a performance impact, etc... This is sorta why I suggested researching them. I think they'll work fine, but I would avoid mixing them in a pool with 512 byte drives, or at the very least mixing them in the same vdev. Overall, I expect ZFS to handle the 4kn's, they're not all that unusual these days, and SSD's are virtually always lying about their geometry, so it's likely a problem that's been handled.

Cables look like the solution... I'm a fan of HGST drives, but I'm a former employee. :)

 

[Octopuss]

I tried looking for other brands, but there is no good list of "everything", and 4kn disks aren't actually that common on Ebay, and those that are there are expensive.
What I found seems to be a pretty good deal after all.

 

[Octopuss]

Btw, chinese cables? Suspiciously cheap? Yes or no?

1M MINI SAS 36P SFF-8087 TO 4 SFF-8482 CONNECTORS ADAPTER With SATA Power Cable | eBay

Internal 36 Pin Mini SAS SFF-8087 Host to 4 SFF-8482 Target SAS Hard Disk and SATA Power Cable. · Internal Mini SAS SFF-8087 to (4) SFF-8482 connectors with SATA power. Target: SFF-8482 SAS connector With SATA 15pin power connector 100cm.

www.ebay.com

In fact, are there any other variations of the cable I posted pic of a little earlier? Still with SATA power connector of course.

 

[rvassar]

Btw, chinese cables? Suspiciously cheap? Yes or no?

1M MINI SAS 36P SFF-8087 TO 4 SFF-8482 CONNECTORS ADAPTER With SATA Power Cable | eBay

Internal 36 Pin Mini SAS SFF-8087 Host to 4 SFF-8482 Target SAS Hard Disk and SATA Power Cable. · Internal Mini SAS SFF-8087 to (4) SFF-8482 connectors with SATA power. Target: SFF-8482 SAS connector With SATA 15pin power connector 100cm.

www.ebay.com

In fact, are there any other variations of the cable I posted pic of a little earlier? Still with SATA power connector of course.

At a full 1 meter, they seem kind of long for your case... No? Otherwise, from a technical standpoint... It's the info that's missing. No signal integrity spec. Are they 6 or 12gb SAS, etc...? BTW - Are you going to mix SATA & SAS on the same HBA?

They're a bit cheaper than when last I bought, but there's no VAT / Import fee info, so I'm guessing it's not too cheap. But remember you're buying a no-name item from China. It's likely going to be something that failed SI test in the last 30 minutes of the graveyard shift, got binned sub-spec, hustled out the side door of the factory while the boss isn't looking... And then sold on eBay by some factory worker's grandmother... I would look for something similar via <large e-retailer in your country>.

 

[Octopuss]

That's one of the first cables with appropriate connectors I found, of course I don't want one metre long.
Everything is made in China, and the three times as expensive cable from "normal" eshops could very well be exactly the same one.... you never know.

 

[rvassar]

That's one of the first cables with appropriate connectors I found, of course I don't want one metre long.
Everything is made in China, and the three times as expensive cable from "normal" eshops could very well be exactly the same one.... you never know.

True, but I'm trying to save you the headache. A local e-retailer has to comply with the laws of your country, and this likely include recourse for you if the product is not as specified or defective. That alone is worth double the $10 we're talking about...

Here's a similar cable for $3 more... Yes it's made in China. Prime shipping, delivery tomorrow here for me in Texas, 30 day return, etc...

Amazon.com

My advice is of course entirely free. :)

 

[Octopuss]

So the disks are finally up and running after two days of cursing (see my other thread from today).

Seems ok, doesn't it?
While I trust the seller (who uses Hard Disk Sentinel which I highly approve of), I'll run some tests on them myself just to make sure.

 

[rvassar]

10k hour HGST's are hard to argue with. Do long SMART tests, and some burn in testing.

 

[rvassar]

Also... Went thru the other thread... I agree on the pin 3 spec change. If I ever meet the people the dropped that in the spec revision, I promise I will give them the verbal abuse they deserve. :)

 

[Octopuss]

Also... Went thru the other thread... I agree on the pin 3 spec change. If I ever meet the people the dropped that in the spec revision, I promise I will give them the verbal abuse they deserve. :)

Yeah. Basically I am forced to use dinosaur connector that looks about as stable as my psyche.
Like I know I am boomer-old by now, but I don't need this relic of the past to remind me of that.... lol

 

[Octopuss]

Does anyone know how to run this? https://github.com/ezonakiusagi/bht
I found it referenced in some thread over here and it links to ServeTheHome forums, but I can't get it to work. Obviously not knowing jack shit about Linux doesn't help....

 

[Alecmascot]

For 4 drives you can run badblocks concurrently as per this resource :

Hard Drive Burn-in Testing

@jgreco did a nice system build/test/burn-in guide here, but I (and many others) found the details a bit lacking in the hard drive section. He mentions S.M.A.R.T. tests, but doesn't go over how to run them, or how to view the results, etc. and...

www.truenas.com

 

[Octopuss]

Yea I guess, but that script has some really useful features, like the status etc.

 

[Octopuss]

Observation after a short time of runtime: the disks are HOT as hell! They aren't really doing anything (besides long S.M.A.R.T. tests running), they sit outside of the case, and I can barely keep my hand on them. That sounds bad, right? I am not sure what the optimal temperature for a disk is, and there seem - as far as I remember - to be conflicting opinions about this, but I'll definitely have to add a fan blowing on the disk cage when I'm done testing and will reassemble the server.
edit: current reported temperatures on the disks vary between 52 and 61°C.