Been finding some good deals on 2.5 disks lately, but have never bought one before. Have a couple of 3.5 disks on the other hand in my Unraid server. Wondering how much it matters wether I get a 2.5 or not? What form factor do you prefer/usually go for?
Just buy CMR
Probably best to go with something in the 3.5" line, unless you’re going enterprise 2.5" (which are entirely different birds than consumer drives)
Whatever you get for your NAS, make sure it’s CMR and not SMR. SMR drives do not perform well in NAS arrays.
Many years ago I for some low cost 2.5" Barracuda for my servers only to find out years after I bought them that they were SMR and that may have been a contributing factor to them not being as fast as I expected.
TLDR: Read the datasheet
Whatever you get for your NAS, make sure it’s CMR and not SMR. SMR drives do not perform well in NAS arrays.
I just want to follow this up and stress how important it is. This isn’t “oh, it kinda sucks but you can tolerate it” territory. It’s actually unusable after a certain point. I inherited a Synology NAS at my current job which is used for backup storage, and my job was to figure out why it wasn’t working anymore. After investigation, I found out the guy before me populated it with cheapo SMR drives, and after a certain point they just become literally unusable due to the ripple effect of rewrites inherent to shingled drives. I tried to format the array of five 6TB drives and start fresh, and it told me it would take 30 days to run whatever “optimization” process it performs after a format. After leaving it running for several days, I realized it wasn’t joking. During this period, I was getting around 1MB/s throughput to the system.
Do not buy SMR drives for any parity RAID usage, ever. It is fundamentally incompatible with how parity RAID (RAID5/6, ZFS RAID-Z, etc) writes across multiple disks. SMR should only be used for write-once situations, and ideally only for cold storage.
Seagate has the very well earned nickname of Seabrick.
2.5" disks are SMR, you don’t want that in a raid.
For the record, so are a lot of 3.5s. Always read up on your drives before buying.
Here you can check if a drive is CMR or SMR:
https://nascompares.com/answer/list-of-wd-cmr-and-smr-hard-drives-hdd/
Thanks. But sad that this list is needed.
It’s actually a big improvement for drives that don’t need a constant transfer rate. Fewer platters and/or higher data density. It’s helped push capacity up for 2.5" drives. I use a couple for cold backups and I appreciate the larger capacity in a small format.
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Awsome resource. You win the Internet today.
SMR ? What is that
Basically the write head writes over part of the magnetic track below the current track, reducing the physical size of each data and increasing how much data can be stored on one side of a disk.They’re bad for random writes because the drive would need to rewrite data in the track below it as well.
SMR is a relatively new disk format technology that makes drives cheaper but writes slower, which can be noticeably bad in a NAS, especially if you are using a write-intensive RAID type. Most disk manufacturers will have drives meant for NAS like WD Red or Seagate Ironwolf, and they are almost all CMR and not SMR.
WD reds I believe are smr, wd red pros are cmr, or at least that was a thing for a while that WD did silently.
Indeed, it’s worth explicitly checking every drive you buy if you are using it in a NAS.
Important note; some WD Reds are still SMR. You have to check which specific type.
i have had SMR drives slow to about 2MB/s with sustained sequential writes. “noticeably bad” really undersells how terrible they are.
the 3.5" barracuda disks are SMR. the barracuda pro disks are all CMR. https://www.seagate.com/products/cmr-smr-list/
You’ll usually want 3.5" on anything that isn’t a laptop for the price and higher max speed
And theoretical reliability. Stuff breaks down quicker at smaller sizes says my lizard brain
Smaller stuff has smaller mass and therefore can be more reliable.
There were portable mp3 players with mechanical hard drives that were reliable despite extreme abuse.
Oh man, I remember a Philips mp3 player I had for the longest time as a kid. You could hear the little clicks of the hard drive. Lost it on a hike, unfortunately.
I dunno I RMA’d my Nomad so many times.
Smaller stuff has to be more complex to get to the lower mass, which is usually what causes the biggest issues. The hdds in those ipods had some extra stuff to make them more reliable, but even then, move them too quickly and they show it.
Smaller doesn’t need to be more complex. 3.5" drives weren’t more complex than 5.25" drives.
A smaller head means a smaller drive actuator. Less mass and smaller size means it can compensate much quicker in response to vibration detection.
Back when full height 5.25" drives were the norm, you couldn’t pick up your PC while running without causing an error. Those tiny CF card sized drives failed but took extreme abuse compared to big drives.
I tell my wife 3.5" is more reliable but she’s not buying it :(
Except the mp3 players from Archos, which gave up after setting up. Twice.
Man my 6000 was immortal. Outlived 2 desktop drives and survived a car roll while in use. I was convinced they had made some blood pact with Nokia lol.
I got mine, moved some songs into it and an hour into listening the drive started clicking and the player was dead. Amazon replaced it and it was exactly the same. I forgot what model it was, but the discs were extremely fragile.
In general laptop drives were a gamble so it’s not shocking. I’m curious if I got a later batch or something or just got lucky.
That was one of those 1 and something inch tiny drives. They were crap
I think 3.5" are usually priced better per tb than 2.5" drives and performance is usually better too. So unless you feel like burning money for an inferior solution, are have some space constraints that doesn’t allow 3.5" drives, I wouldn’t go with 2.5" drives. They’re more energy efficient though, but you’d need a fuckton of drives for that to make a worthwhile difference in your power bill.
The key here is “better performance at similar price points”. There are absolutely amazing 2.5 drives made for server applications, but they cost so much money you’re better off getting SSD these days.
Speaking of which, you should consider SSD.
Absolutely no shot I can afford 40 TB of SSDs for my NAS
Depending upon your storage setup, may be able to make use of an SSD cache drive for a larger rotational drive array, though.
Man, I remember when Zip Disks were a big deal and a GB was a lot of storage.
One of my clients referred to Zip disks a few days ago. That really sent me back. Only my rich friends had Jaz drives, whereas the rest of us were still using Zip disks and optical media. Those early USB thumb drives at USB 1.0 speeds were also painfully slow.
My portable storage journey progressed from 5.25” floppy disks, 3.5” diskettes, Zip disk, CD-R/RW, DVD-R/RW, 2.5”/3.5” external HDDs and now portable NVME SSDs.
I remember learning that 3.5" disks were still called “floppy” disks, despite being rigid plastic. My teacher took apart a disk and showed us how the inside was a film, but all that did was encourage us to take apart the disks and make desk toys out of the springs.
No LS-120 or eSATA drives. :-)
That’s fair.
Ssd for boot but not cost effective for nas. Nor do I trust their longevity.
SSD longevity seems to be better than HDDs overall. The limiting factor is how many write cycles the SSD can handle, but in most cases the write endurance is so high that it’s unreachable by most home/NAS systems.
SSDs are however really bad for cold storage, as they will lose the charge stored in their cells if left unpowered too long. When the SSD is powered it will automatically refresh the cells in the background to ensure they don’t lose their charge.
Thanks, yeah i’ll go with 3.5" ones then, only reason i considered it was because of some really good deals. But I’d rather stick with having a uniform set of drives. Thanks for your input!
3.5" are cheaper, go up to higher capacities (2.5" maxes out at only 5TB IIRC), and are easier to find cheap in used/refurb formats.
I wouldn’t use 2.5" unless you absolutely had to for some reason.
The 2.5" drives are significantly more power efficient, often by a factor of 10. They also tend to be less noisy and produce less heat.
So in a small form factor NAS that isn’t under heavy load, 2.5” drives are usually the better option.
It looks like about 2-3W with 2.5" vs 6-8W with 3.5"
So 3.5" drives are going to be more efficient, since you can get one that’s 4x the capacity (20TB vs 5TB) for only a little over double the power usage.
Less noise is definitely a bonus if your NAS sits next to your workstation or something though.
It is true that if you need a lot of space at some point 3.5" are going to be more efficient per GB, but usually people don’t need hundreds of terabyte storage in a home NAS.
For normal applications in a home NAS that mostly sits idle, 2.5" drives run at about 1W and most are design to be able to be powered by normal USB, meaning 2.5W max.
3.5" drives on the other hand are usually designed for datacenter use, where power efficiency is a low priority and they usually take 5-10W in normal operation and and easily 15W when spinning up.
I don’t even have all that much storage (18TB usable), the other side of things is I’d need 8x 5TB 2.5" drives in RAID 10 to be equal my 2x 18TB 3.5" drive mirror I have now, which means I’d need to add an HBA card that also consumes more power. Even if I ran RAIDz2 I’d still need 6 drives.
Price is another factor, from some poking around 2.5" is around 2x the cost of what I paid for my 3.5" drives.
Yes. Chuck some 5TB Seagate externals. They’re way less pain in the ears, cooler and quieter.
Power-consumption.
Also, the vibration produced by the 2.5" drives is less, but they’re more-sensitive to it, to begin with.
I’d not even consider spinning-platter drives, nowadays, though:
SATA SSD’s for a NAS strike me as being the sanest choice.
Samsung what are those called, Evo drives?
excellently-high MTBF, ultra-short ( compared with rotating-platters ) seek-time ( literally orders-of-magnitude quicker ), etc.
I don’t know of ANY reason to go with spinning-platters, nowadays.
( & I’m saying that as a guy stupid-enough to have not realized this in time, & who spent money on such a thing, when SSD’s really were the answer )
Cost? I bought 3x 8TB Ironwolf drives for £115. That’d cost about £1.5k in SSDs.
Running ZFS on consumer SSDs is absolute no go, you need datacenter-rated ones for power loss protection. Price goes brrrrt €€€€€
I too had an idea for a ssd-only pool, but I scaled it back and only use it for VMs / DBs. Everything else is on spinning rust, 2 disks in mirror with regular snapshots and off-site backup.
Now if you don’t care about your data, you can just spin up whatever you want in a 120€ 2TB ssd. And then cry once it starts failing under average load.
Edit: having no power loss protection with ZFS has an enormous (negative) impact on performance and tanks your IOPS.
I don’t know of ANY reason to go with spinning-platters, nowadays.
Price per terabyte is lower on HDDs. For bulk storage they are currently the best path. SSDs are catching up though, and there are cases where a SSD based NAS does make sense. But most folks at home don’t have the network capability to fully utilize their speed. Network becomes the bottleneck.
Well first off, if you’re building a NAS, build it out of drives that are rated for NAS use. Seagate’s IronWolf line is a bit pricier than their BarraCuda but has better transfer speeds and (more importantly) better resiliency to vibration, which is important if you’re putting a half dozen drives in the same enclosure and don’t want them to fail prematurely.
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I’ve seen in this thread:
Fewer Letters More Letters CF CloudFlare NAS Network-Attached Storage RAID Redundant Array of Independent Disks for mass storage SATA Serial AT Attachment interface for mass storage SSD Solid State Drive mass storage ZFS Solaris/Linux filesystem focusing on data integrity
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Depends on your NAS server. If you’re like me and using an old optiplex, you can fit WAY more 2.5" drives in it, and they’re pretty cheap. If you have an actual proper server chassis, then you probably want 3.5" NAS hard drives cuz warranty and all that.
Well you’re looking at it. 3.5in is faster
Generally higher storage sizes too, right? So if you want the max storage, go with 3.5"
Cheaper too I guess
I recently started getting my drives from serverpartdeals 3.5". The refrubs seem to work great for my use case of just media. I have a second unraid server that is just 2.5" ssd’s and 4 nvme’s that I use for my personal files and photos since it’s a much smaller and low power build I can stuff a bunch in a mini itx case so 2.5" is great for that
I don’t think there’s anything between.
lol - just realised that probably wasnt the best formulation for a question ahah
The 2.5 unit I have runs cooler and consumes less power. It’s also more expensive.
