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.
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.
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.
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
2,5" drives are usually slower, but still about 5400rpm, which is on par with many NAS-specific 3,5" drives.
Also, you show Barracudas here, and I’d warn against them in a NAS environment. If you pick among Seagates, Ironwolf series might be what you need; otherwise, WD Reds reign supreme, just check that the specific drive you’re looking for uses CMR, not SMR.
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.
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.
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 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.
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.
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