I’m migrating my data from a Synology NAS to a FreeNas Mini XL and have a question. I’m starting out with two WD Red NASware 3 TB drives in the FreeNAS, and I plan to add more drives as I migrate data. Ultimately, I will have five WD Red NASware 3 TB drives installed.
I know that to start, I’ll either have to set up a RAID-1 (mirror) since I only have the two disks (or set up a smaller pool using the SSDs that came with the FreeNAS). Once I start adding more disks, can I change the RAID type without losing my data?
Or would I be better off buying another 4TB external drive and migrating my data over to it then pulling all of the disks at once and installing them into the FreeNAS? If so, what type of setup would you recommend? I have about 6 TB of data total right now.
I had to do something similar when I realized that raidz1 wouldn’t cut for my need of redundant drives & future expansions. Would recommend.
Honestly, considering you’ll have five 3TB drives, I’d argue raidz1 is fine unless you’re feeling squeemish & want raidz2 for up to 2 disks failing before data loss.
3TB drives are small enough that I’d argue the risk of additional HDD loss during a resilver is minimized compared to >8TB drives.
You can add more mirrors (in traditional parlance, turning your RAID1 into a RAID10) but you can’t convert-in-place to a RAIDZ1 (RAID5) or RAIDZ2 (RAID6) - you have to start with that configuration from the beginning.
With a plan towards having 5x 3T drives in the end, that to me would suggest a RAIDZ2 - this would give you about 9T of usable space (before compression) and two-drive fault tolerance. If that sounds like a good mix to you, then I’d consider finding a way to do that complete backup-and-restore cycle. The additional drives can also potentially become a second level of backup (because as many here will attest to, “RAID is not a backup”) for your future configuration.
As you can see there is no obviously correct answer for this specific pool in terms of raidz1/z2 (arguably z3 I guess). The correct answer for YOU will have to do with making the choice based on your risk tolerance, budget, and hardware restraints.
Just don’t make it into a stripe please (any disk loss = data loss).
Please verify that these are NOT SMR disks. While SMR, (Shingled Magnetic Recording), disks can appear to work. And may work for years, they are not a good fit for TrueNAS’ ZFS.
Thank you everyone. My plan is to move everything to two 4TB external disks and then put all five of my disks into the FreeNAS. My next question is, down the road if I buy three more disks (it holds eight total), would I be able to just add them to my pool or do I have to create a second pool? That’s assuming I use either RAIDz1 or RAIDz2 for the pool initially.
Also, I’m seeing conflicting answers on the SMR/CMR topic. It appears they are probably CMR as they are manufactured prior to 2019. Also, I should note that I ran them in an Amahi Home Server for a few years already (granted not using ZFS).
If you’re considering buying 3 more drives down the road, you can use raid expansion on latest version of TrueNAS Scale to expand the pool with minimal usable space loss (you can then consider if it is worth manually running a script to re-write all your existing files to get this space back afterwards; not a built-in feature due to arguable risks).
If you’re going to have 8 HDDs total, I’m going to change my answer to from “raidz1 no brainer” to “consider raidz2”. Just do keep an eye & make sure you’re using CMR, else I can imagine resilvers, expansions, etc. to give you a VERY bad time.
Indeed, it is a matter of personal choice. But at some point the future of a 5-wide raidz will be to replace the drives with larger ones rather than to throw in more small hard drives—and then the case for raidz2 will become clearer.
I’m pretty set on Raidz2. Right now, I’m in the process of migrating the last of my data to an external hard drive and then I’ll be pulling the drives out of the Synology NAS. I’m assuming when I go to create the pool, it will wipe them (so I don’t need to do anything with them other than plug and play).
Have a great night and thank you all for the information.
Patrick.
