this post was submitted on 27 Jul 2025
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1 big SSD or multiple? New NAS build. (programming.dev)
submitted 5 months ago by rutrum@programming.dev to c/datahoarder@lemmy.ml
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I'm looking to spec out a new NAS. I have a relatively small media collection, that I hope to grow as I digitize more family VHS tapes etc. Right now I have around 4 TB of data, shared across an external drive and my internal ssd.

Whats the best path forward on drives in this new NAS? I've heard advice for buying one big 20TB drive over multiple smaller drives. What's best for mitigation of drive failure? Is that even a concern? If I do multiple drives, should I use RAID?

I'm a little new to this. If you have resources for learning some best practices I'm all ears.

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[–] digdilem@lemmy.ml 2 points 5 months ago* (last edited 5 months ago)

I'm confused that you're talking of buying 20tb SSDs - you must be very rich. Spinny drives are more usually used in homelab archive RAIDs since they are more cost effective at large size and RAID offsets some of the slowness associated with them. I'm going to assume you meant HDDs not SSDs, but the advice applies to both if I'm wrong about that.

Yes, you will want to RAID them. That gives some protection against individual drive failure, and yes, absolutely that is a concern. Whilst the chance of drives failing these days is less than it was, they still do fail without warning, even when relatively new, and because of the bigger sizes, the consequences are greater.

The alternative to RAID is JBOD (Just a Bunch Of Drives) which means lots of individual drives being presented, each with their true size, in multiple shares. Most folk don't want that.

What RAID level you choose depends on:

  1. How many drives you fit. 4+ is good, and "more smaller" is better than "fewer larger" for safety, although the compromise is an extra 10watts or so of power per drive.
  2. Current best practice; Don't use RAIDs 0 or 5 on large arrays. (0 means exponential increase of data loss. 5 is strongly discouraged due to rebuild times of large disks) 6 is good if you have enough disks. 1+0 (mirrored and striped) is reasonable, and the choice I made for mine.
  3. The hardware you're using. Whether a linux PC or a bespoke NAS tool. Whilst the RAID levels are similar, the tools used vary a lot.

Notes:

  • Also, be realistic about the space you need. Don't over-size. Plan for 3-5 years growth, by then you'll be wanting to change because of speed changes or drive failure.
  • Some raid types slow down writing of data, some speed it up. Most are much faster at READing data.
  • https://en.wikipedia.org/wiki/Standard_RAID_levels gives some explanation of the types.
  • Google for "RAID CALCULATOR" for lots of free websites that allow you to see what space different sized drives give you with different RAID levels.
  • Do not omit a strong backup strategy. RAID only protects against some types of hardware failure. A lightning strike, fire, rogue bios or software update, the host dying with an incompatible raid system. Buy disks for backups that aren't in your RAID. (Good branded USB 3 disk and caddies are sensible). Automate backups if you can. Backup only what's not easily replaceable.
  • I wrote some thoughts on backups here.