Other Need disk advice for SSD's

Phishfry

Phishfry

I am looking to fill out a second 24 disk 2U rack mount with drives.
These are Chenbro cases for 2.5" drives and I am not concerned about overall size of array. This is for home lab learning.
I have one 2U rack already filled with Seagate 500GB SAS2 drives but these drives run so hot I am really disgusted and want to pivot to solid state.
So I am looking at SSD's to fill out my second rack. The cooler temperatures might allow me to reduce my fan noise are my thoughts.
Maybe split the SSD's and Seagates to reduce heat. 12/12 each in both cabinets.
I am a fan of Samsung SSD drives but think I have found something from Innodisk. 32GB SSD's for around 10 bucks each.
So to fill the cabinet and have 2 spares will not break the bank. The drives have a 3 Million MTBF rating, but only advertise 470/260 Max sequential.
The write speed is a little disappointing, but the 3 Million hours MTBF is what I like.
Thoughts? Is 32GB a ridiculous small number for a ZFS array? Totaling only around 800GB.
I might front it with some NVMe drives for Arc and log.
Innodisk makes some serious industrial gear and that is what I like to buy. Should I move on?

2.5" SATA SSD 3ME4 | MLC Solid State Drives

2.5 inch SATA SSD 3ME4 is designed as MLC Flash with capacities from 8GB to 256GB. It features wear leveling technology and TRIM technology to prolong lifespan.
www.innodisk.com www.innodisk.com

I bought some 64GB Advantech SSD drives that have serious MTBF but I can't find a quantity of them cheap.
I also have some Samsung PM850 drives as well as SanDisk X300 drives on my search list at much larger capacity.
Nowhere near the MTBF though of industrial drives but with 500/500 Read/Write sequential scores.
Should I quit worrying about MTBF?
 
I am happy with Kingston drives as below.

I have a mirror of those in one PC
Code: 
ada0: <SanDisk SDSSDA240G Z32070RL> ACS-2 ATA SATA 3.x device
ada0: 600.000MB/s transfers (SATA 3.x, UDMA6, PIO 512bytes)
ada0: 228936MB (468862128 512 byte sectors)
An older one is build in a laptop
Code: 
aada0: <KINGSTON SV300S37A120G 583ABBF0> ATA8-ACS SATA 3.x device
ada0: 600.000MB/s transfers (SATA 3.x, UDMA6, PIO 512bytes)
ada0: 114473MB (234441648 512 byte sectors)

The biggest advantage is the absence of noise.
 
The Sandisk Z400s is on my list as they are still available retail.
I don't know if I would use them in a ZFS array though.
Plus: a manufacturers warranty and good speed
Minus: they are a consumer drive
 
Ick, Sandisk, I've had lots of problems with those, computers that won't boot, data corruption.

My go to right now in a 2.5" SATA form factor is the Samsung 860 Evo. The 860 Pro has better longevity, but it's also more expensive.

Though I would consider a small U.2 rack and fill it with Samsung 983 DCT drives. They're actually not that much more expensive than M.2 drives of similar capacity. Last time I looked at U.2 drives they were a lot more expensive. Still you could use lower capacity less expensive M.2 drives with U.2 converter trays and fill a RAID set a lot cheaper, but you lose the hot plug.

Generally I'm using Samsung for all my SSD needs including their 970 Evo Plus M.2 drives, fastest 3.0x4 drives on the market (there are 4.0x4 drives that are faster). They've been serving me well. I'm even using their USB connected T5 portable SSD, really happy with those and no slower than a SATA SSD.
 
I got too hung up on 3,000,000hrs/MTBF that I never calculated what it actually equated to.
Roughly 340 years.
I am not sure I need that level of surety.
So a 1,000,000 hour MTBF drive is fine and dandy. I doubt I will make it another 100 years.
So I can broaden my horizons.
Still want something with high reliability and cheap.
 
Yeah endurance is the main thing to consider and that's expressed in TBW (terrabytes written). For a consumer drive each cell is good for about 600 write cycles, higher for more expensive and enterprise drives. The drive's controllers ensure all the cells get used evenly (wear leveling). So it cycles through all of the drive's memory as much as possible.

The higher the capacity of a drive the higher the TBW, but also consumed space can make a difference since you can't wear level with memory that is not free. So one of the down sides of SSDs is it's better to keep a good amount of free space. With a mechanical drive you can fill it to the brim without concern, but you want to avoid doing that with SSDs.

So there's a couple ways to increase TBW, one is by using a higher capacity drive and the other by using a more expensive drive with higher per cell write cycles. However that comes at a cost in speed (for NVMe at least). Personally I just stick with consumer drives and go higher capacity to get higher TBW. It has the advantage of providing a bigger pool for wear leveling and you get the highest speed.

The speed is crazy on a fast 3.0x4 NVMe drive, it's amazing. First time I benched an Evo Plus the numbers were so high I thought there was something wrong with my benchmark tool.
 
While researching Intel drives I noticed they are not consistant in thier marketing materials
ark.intel.com

Product Specifications

quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more.
ark.intel.com ark.intel.com
One drive expresses endurance as lifetime writes "10 drive writes per day for 5 years"

ark.intel.com

Product Specifications

quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more.
ark.intel.com ark.intel.com
While another expresses lifetime writes as "45 TBW"

On top of that most of these devices are made in China and that really makes me suspicious of the 2 Million hour MTBF figure.
228 years is certainly not accurate but a best case estimation.

Will SSD drives still work as read-only when TBW is maxed out?
 
I wouldn't focus too much on MTBF, as the figures are seriously extrapolated. I remember reading some years ago that Samsung came up with MTBF figures for each model of HDD by doing a one-off test of a large batch for only 24 hours. The MTBF may have some relevance if you have thousands of drives in a data centre, where failures are a daily occurrence and the sample size is large, but it certainly doesn't mean that a single drive is typically expected to last for hundreds of years. Annualised failure rate is probably a more useful metric, although it would still be based on extrapolated empirical data.
 
Phishfry said:
One drive expresses endurance as lifetime writes "10 drive writes per day for 5 years"
Click to expand...
Never seen that one, how big are the writes? If they mean the whole capacity what would be more writes cycles per cell than I've seen for any flash memory, like 20k. Best I've seen for any flash memory in general is 10k.

While another expresses lifetime writes as "45 TBW"
Click to expand...
That would be about right, 45TB divided by 80GB is just about 600 write cycles per cell. Anyway an SSD that small standing on its own would not really be usable, typically you want at least 256GB to get the TBW up high enough.

Keep in mind for a RAID set those TBW numbers add. For a example a stripe with three disks would have triple the TBW of a single drive since each disk only handles a third of the data written.

Personally a I would avoid the Intel brand for SSDs. The Intel 545S is okay as far as 2.5" SATA drives go, but other brands are cheaper. At one point their consumer stuff was cutting edge, but they seem to have given up on advancing their line. Now its slow and expensive. Their enterprise stuff is up there speed wise but the prices are really high, not competitive at all.

In any case SATA is falling by the wayside for M.2 and U.2 NVMe. There's also other enterprise NVMe form factors vying for popularity. M.2 is pretty sewn up for consumer.
 
Phishfry said:
ark.intel.com

Product Specifications

quick reference guide including specifications, features, pricing, compatibility, design documentation, ordering codes, spec codes and more.
ark.intel.com ark.intel.com
Click to expand...

I'd stay away from the Intel DC 3500 series. We have a number of 1TB S3520 (SATA) and P3520 (PCIe) drives that randomly stops responding after a couple of weeks - and then if we just let them sit there will automatically reappear again after a couple of more weeks.

Tried updating the firmware on the drives but nothing has helped so far. Powercycling makes them work again for some time.

The S3520 (SATA) drives are mostly used in mirrored boot disk pairs so works mostly fine (unless both parts of the mirror decided to go silent at the same time), but when the P3520 (PCIe) drives decide to take a hike it takes down the machine...

(Seen on FreeBSD 11.2 & 11.3 running on Dell PowerEdge 730xd servers with Dell HBA330 (LSI SAS3008) controller)
 
I am throughly vested in the Samsung PM983 for PCIe drives.
They have exceeded my expectations.
I just purchased my 6th one. I have been buying them for a few months now. 960GB is a good size for me.
No good deals on any Intel Enterprise SSD's that I can find.
I have added Toshiba PX02 medium endurance drives that use SAS3 interfaces to my list.
 
I think Samsung is the most premium SSD brand right now. Another brand I think is high quality is PNY. There's a few major overseas brands doing 4.0x4 stuff (PCIe 4.0 by 4 lanes) , but it's so new there's not much out there on reliably.

Of course only the latest AMD platform supports PCIe 4.0 at this point. I think it's kind of funny that Intel is holding back on releasing PCIe 4.0 stuff under the guise that 3.0 is faster than any consumer needs as it stands. Kind of indicates their desire to stop putting money into developing their SSD line languishing as it is.

Right now 4.0x4 drives are about a third faster than 3.0x4, but the memory chips are the limiting factor instead of the bus speed. The bus ceiling is double. Samsung will be releasing a 4.0x4 enterprise product soon if not already. The thing about the Samsung enterprise stuff is it's not a whole lot more pricey than the consumer stuff. Not at all the case for Intel. There's some enterprise drives that do 3.0x8 via PCI slot which also doubles the bus speed compared to 3.0x4, but all the ones I've seen are very expensive...ehem Intel.

SSD is all about speed so it only makes sense to shoot for the fastest stuff. Otherwise if looking for longevity HDD is a more viable option. Still 3.0x4 is crazy fast. With a single Samsung 970 Evo Plus NVMe drive I bench over three gigabyte per second on both sequential read and sequential write, just wow.
 
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