SOLVED Anyone use this low cost 12x2.5" drive bay Backplane?

[stevenmcw]

Hi,

Im just starting my first build of FreeNas.


i have been looking at this lower cost backplane however data sheet states that it only supports up to 14.5mm 2.5" Hard Drives,

there is no drive at the height.

they are 12Gb/s using MiniSAS HD (SFF-8643) that are rebranded so there a a few model numbers see below


N-127SS

JJ-127SS

BP-127SS

some sites say it supports 15mm i think the 0.5mm is for the anti vibration at the bottom and by screwing it in the give the 15mm heigh.

My problem is that no compony i have found so far that is selling it will accept returns if the box has been opened.

if someone is using one of these could you please confirm what hard drive are 15mm and what models you are using.



Thanks



Steven

 

[Stevie_1der]

Why do you want 2.5" HDDs instead of the cheaper 3.5" ones?
Physical space requirements?
Or do you have a bunch of 2.5" HDDs already at hand?

Or are you going all-SSD?
SSDs are 7 or 9.5mm mainly, so the 14.5mm max shouldn't be a problem.

What hardware are you planning in detail, and which use-cases?

 

[Chris Moore]

they are 12Gb/s using MiniSAS HD (SFF-8643) that are rebranded so there a a few model numbers see below

Unless you are using SSDs, 2.5" drives have much less performance than 3.5" drives while being more expensive on a price per TB basis. There is no excuse for using them Why would you even consider it?

 

[Chris Moore]

i have been looking at this lower cost backplane however data sheet states that it only supports up to 14.5mm 2.5" Hard Drives,

there is no drive at the height.

This is the thickness of the drive that the backplane is made for, if you didn't find them, it is because you didn't look hard enough:
https://www.serversupply.com/HARD DRIVES/SAS-12GBPS/1.8TB-10000RPM/SEAGATE/ST1800MM0018.htm

 

[stevenmcw]

Why do you want 2.5" HDDs instead of the cheaper 3.5" ones?
Physical space requirements?
Or do you have a bunch of 2.5" HDDs already at hand?

Or are you going all-SSD?
SSDs are 7 or 9.5mm mainly, so the 14.5mm max shouldn't be a problem.


What hardware are you planning in detail, and which use-cases?

Hi

im trying to achieve getting the most hard drive space

My case is "4u Chembro" RM42300 with addition "Drive cage, 3x5.25"

This give me a total of 6x5.25" external and 6x3.5" internal as well as a slimline ODD or SDD.

I currently using a temporary motherboard, but i do have a "Perc H310"

yes I do have a lot of 2.5" HDD

3x147GB SAS
3x72GB SAS

2x4TB SATA

and a couple others.

Im also looking to future proof hence 12Gb/s

If i where to get the backplanes mentioned i would have a 24x hotswap and 7x internal.

 

[stevenmcw]

Unless you are using SSDs, 2.5" drives have much less performance than 3.5" drives while being more expensive on a price per TB basis. There is no excuse for using them Why would you even consider it?

Im not looking to buy everything at the same time that would be to expensive for me. i am using parts i currently own give me a bit of future proofing, i am not requiring speed atm just at the moment just largest amount of storage when i bought the 2x4TB HDD they worked out less than the 3.5" drive of the same size.

4TB drives are "Seagate Guardian BarraCuda ST4000LM024"

 

[stevenmcw]

This is the thickness of the drive that the backplane is made for, if you didn't find them, it is because you didn't look hard enough:
https://www.serversupply.com/HARD DRIVES/SAS-12GBPS/1.8TB-10000RPM/SEAGATE/ST1800MM0018.htm

Yes i know it supports those types of drives but the your link states that drive is 15mm heigh. As i said in the original post most site say that only support drive height up to 14.5mm.

I cant afford to be out ~£200 if it does not work.

 

[jgreco]

Unless you are using SSDs, 2.5" drives have much less performance than 3.5" drives while being more expensive on a price per TB basis.

Fact not in evidence. *SOME* 2.5" drives perform poorly, yes. If you do an apples-to-apples, what you said is generally not true, but it is sometimes hard to come up with comparable drives. The number of high performance 2.5" drives is in very short supply here in 2019 as SSD prices drop.

There is no excuse for using them Why would you even consider it?

You get good density in a smaller space. More independent mechanisms has been a big thing for ZFS for years. Back in ~2015 when I built our VM ZFS filer, it was 26 disks in 2U (24 front/2 rear), with 2TB being the largest reasonable drive available. At the time, a 12 3.5" disk 2U chassis with 6TB drives would have been possible, but would only have yielded 3 vdevs, whereas the 24 bay unit yielded 8 vdevs.

Raw space there favors the 3.5" (6TB * 12 = 72TB raw) but pool space would only be 18TB (3 * 6TB) or 9TB "usable" space.

By way of comparison, the 2.5" yields less raw (2TB * 24 = 48TB) but pool space is 16TB (8 * 2TB) or 8TB "usable" space - slightly less space but with more than twice as many vdevs. This might cause you to have to reconsider performance from a different angle. It can definitely come out far ahead of 3.5" if done right.

The other significant factor is that SSD hasn't been delivered in the 3.5" FF for quite a few years, so a potential future conversion to all-SSD would strongly favor the 2.5" chassis.

Unfortunately, it's been suckville in 2.5" land for performance or high capacity HDD these past few years. Capacity has topped out at 2TB for usable drives; beyond that you can get up to 5TB if you can stomach SMR drives, which are poor for ZFS. My go-to 2.5" HDD for years has been the WD Red 2.5" 1TB. At a wholesale cost of around $65, I can get a decent 1TB SSD such as the WD Blue for just about twice the cost. It feels like we've hit the end of the road for the small drives. Both the WD Red WD10JFCX and the Spinpoint M9T 2TB are 2013-era drives that are "still being produced" but with no larger drives on the horizon -- six YEARS later.

 

[Chris Moore]

Im also looking to future proof hence 12Gb/s

i am using parts i currently own give me a bit of future proofing

You keep saying that, but it doesn't mean what you think it means.... There is no such thing as "Future Proof", just forget that marketing buz-word.

 

[Chris Moore]

Im not looking to buy everything at the same time that would be to expensive for me.

How much can you spend?

My case is "4u Chembro" RM42300 with addition "Drive cage, 3x5.25"

This was a bad investment. You should have come asking questions first.

4TB drives are "Seagate Guardian BarraCuda ST4000LM024"

4TB 3.5" drive: https://www.newegg.com/Product/Product.aspx?Item=N82E16822179009 -- $102.44
4TB 2.5" drive: https://www.newegg.com/Product/Product.aspx?Item=9SIA8HW8S91143 -- $116.95
I don't know where or how you got such an idea that the smaller drive is less expensive. It is NOT and on top of that it performs worse. I have done real-world testing for my organization in my job. You can review the manual for the documented differences:
https://www.seagate.com/www-content...op-fam/barracuda_25/en-us/docs/100804767c.pdf
https://www.seagate.com/www-content...a-fam/barracuda-new/en-us/docs/100804656b.pdf

I can't afford to be out ~£200 if it does not work.

I am not suggesting that you obtain any mounting hardware for any type of 2.5" hard drives. It would all be wasted money.
The best value in hard drives is in the 3.5" drives. Please review this document:
https://www.ixsystems.com/community/resources/disk-price-performance-analysis-buying-information.62/
It might also help if you look at this document:
https://www.ixsystems.com/community...-comparison-spreadsheet-to-find-best-tib.116/

 

[Chris Moore]

By way of comparison, the 2.5" yields less raw (2TB * 24 = 48TB) but pool space is 16TB (8 * 2TB) or 8TB "usable" space - slightly less space but with more than twice as many vdevs. This might cause you to have to reconsider performance from a different angle. It can definitely come out far ahead of 3.5" if done right.

What about the cost?

At a wholesale cost of around $65, I can get a decent 1TB SSD such as the WD Blue for just about twice the cost. It feels like we've hit the end of the road for the small drives. Both the WD Red WD10JFCX and the Spinpoint M9T 2TB are 2013-era drives that are "still being produced" but with no larger drives on the horizon -- six YEARS later.

I was just looking at the 16TB Seagate SSD yesterday:
https://www.newegg.com/Product/Product.aspx?Item=9SIA6ZP8EM0392
If the price were just a bit more reasonable...

 

[jgreco]

What about the cost?

To get similar performance with 3.5 would require swapping out the SC216BE16 for the 4U SC846BE16 at a similar cost, but ongoing opex increase of 2U.

Opex modification: Rack space costs $47/U/month so over a five year lifecycle there's an additional opex of $5640.

Capex modification: WD Blue 2TB 3.5" costs $61/per whereas Spinpoint M9T costs $85/per, cost differential is $24/drive. The 2.5" chassis can take 26, including two spares, so total storage cost is $2210 for 2.5 whereas only $1464 for the 3.5. Obviously the 3.5 is somewhat cheaper.

Total cost delta over five years works out to $4894 cheaper for the 2.5.

If you stick with the 2U 12 bay, the 3.5 comes out *much* cheaper, but also has sucktacular performance compared to the 2.5.

Are we having fun yet? ;-)

I was just looking at the 16TB Seagate SSD yesterday:
https://www.newegg.com/Product/Product.aspx?Item=9SIA6ZP8EM0392
If the price were just a bit more reasonable...

Well if you look at it the right way, it's only around $380/TB. Cheapo SSD is around $110-120/TB right now. If you look at TBW, that Seagate is rated at 28336TBW, so again dividing to 1TB, that's about 1800TBW-per-TB. That's better than the Samsung 860 Pro's 1200TBW. You can get the 4TB model of *that* for around $950, so 4x that is $3800, so the Seagate unit's a bit of a price premium but it also supports SAS 12Gbps and has better endurance and other stats working for it. I don't think the price is super out-of-line for a top-of-the-line SSD...

What I really want to see is another 50% knock off the cheapo SSD. I can work with that. ;-) This might be the year for that.

 

[Chris Moore]

Are we having fun yet? ;-)

I am.

 

[jgreco]

You keep saying that, but it doesn't mean what you think it means.... There is no such thing as "Future Proof", just forget that marketing buz-word.

Especially as SATA seems to be EOL at 6Gbps. We are not likely to see HDD's that require more than 6Gbps. I don't think there's any SATA WG working on a faster standard.

While there are a modest number of 12Gbps SAS HDD's and SSD's, the main thing going for the 12Gbps SAS HDD is the dual port SAS. There is no chance a SAS HDD will have any significant benefit from 12Gbps, but the redundancy is nice.

12Gbps SSD's are definitely a thing, though, as @Chris Moore pointed out above. Unfortunately, they don't hold a candle to NVMe. SAS-4 (24Gbps SAS) is under development, but whether this is ever going to see any serious traction is in doubt. It's probably going to end up being a technology used between HBA/RAID and external disk shelves, a place where the speed would be useful, but SAS-4 HDD's are extremely unlikely, and SAS-4 SSD's, I doubt that too.

24Gbps SAS-4 in an x8 wideport would give you around 19.2GBytes/sec which means you could run 96 HDD's on an expander without contention.

However, a single NVMe device is already easily capable of 3.5GBytes/sec, so (just for apples-attached-to-oranges comparison) you would only fit about 5 of those on SAS-4 before being oversubscribed, and then the question of why you'd introduce a controller in there that would act to introduce latency becomes a serious question. The only serious answer I've seen to that is "RAID", because some of us like to build our hypervisors with redundant datastores. But LSI will do this for you using NVMe; see the 94xx series of controllers and U.2. So SAS-4 has been passed up before it is even a standard.

More catastrophically, flash has caused some serious rethink of form factors. M.2 is incredibly small but has some liabilities. EDSFF/M.3 is another option. U.2 is nice but might not be a long-term survivor because of the 2.5 form factor that wastes quite a bit of space. There's a lot of uncertainty in this space, unfortunately.

 

[stevenmcw]

So for anyone who might be considering purchasing this.

I decided to purchase the backplane as i found a company that would accept returns if opened and even though the spec sheet specifies max HDD 14.5mm it does in fact allow 15mm HDD to be used.

I am very pleased with the purchase.

 

[jgreco]

Be careful. The fact that you can cram a 15mm HDD in doesn't mean that's a good idea. You do actually need some airflow around drives or they can start to get nice and toasty when running continuously. If you are eating space that was meant for cooling, then you may reduce the drive's useful lifetime or even kill it outright.

 

[stevenmcw]

Be careful. The fact that you can cram a 15mm HDD in doesn't mean that's a good idea. You do actually need some airflow around drives or they can start to get nice and toasty when running continuously. If you are eating space that was meant for cooling, then you may reduce the drive's useful lifetime or even kill it outright.

I previously had this icydock ToughArmor MB994IPO-3SB
https://www.icydock.com/goods.php?id=149

i have been running that for a long time now with no problems.

The new backplane has a bigger air gap between the bays and even though an 80mm fan would have been better it is still get better airflow in comparison. the is enough space that i should be able to modify the back to accommodate a Noctua fan in conjunction with a fan controller with heat probes.

Thanks for your input.