Hello, I currently have a home server mainly for media, in which I have an SSD for the system and 2 6TB hard drives set up in raid 1 using mdadm, its the most I can fit in the case. I have been getting interested in ZFS and wanting to expand my storage since it’s getting pretty full. I have 2 12TB external hard drives. My question is can I create a pool (I think that’s what they are called), using all 4 of these drives in a raidz configuration, or is this a bad idea?
(6TB+6TB) + 12TB + 12TB, should give me 24TB, and should work even if one of the 6TB or 12TB fails if I understand this correctly.
How would one go about doing this? Would you mdadm the 2 6TB ones into a raid 0 and then create a pool over that?
I am also just dipping my toes now into Nixos so having a resource that would cover that might be useful since the home server is currently running Debian. This server will be left at my parents house and would like it to have minimal onsite support needed. Parents just need to be able to turn screen on and use the browser.
Thank you
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I believe ZFS works best when having direct access to the disks, so having a md underlying it is not best practice. Not sure how well ZFS handles external disks, but that is something to consider. As for the drive sizes and redundancy, each type should have its own vdev. So you should be looking at a vdev of the 2x6TB in mirror and a vdev of the 2x12TB in mirror for maximum redundancy against drive failure, totaling 18TB usable in your pool. Later on if you need to add more space you can create new vdevs and add them to the pool.
If you’re not worried about redundancy, then you could bypass ZFS and just setup a RAID-0 through mdadm or add the disks to a LVM VG to use all the capacity, but remember that you might lose the whole volume if a disk dies. Keep in mind that this would include accidentally unplugging an external disk.
Yeah definitely wanting the redundancy, most of what I will be storing will not be life changing if lost just a big inconvenience, and for the life changing stuff I plan on having it backed up to cloud storage.
You’ve got some decent answers already, but since you’re getting interested in ZFS, I wanted to make sure you know about discourse.practicalzfs.com. It’s the successor to the ZFS subreddit and it’s a great place to get expert advice.
Thank you for that will have to have a look into it since I am quite new and I am not completely sure how to go about things in a way to not regret it later down the line in half a year or so.
Make sure you understand volume block size before you start using it. It has a big impact on compression, performance and even disk utilization. In certain configurations you may be surprised to find out as much as 25% of your disk space (in addition to parity) is effectively gone and it is untrivial to change the block size after the fact.
That’s definitely I have to look into, the nixos page on ZFS had a link to a ZFS cheat sheet of sorts that I have been trying to wrap my head around, thanks for pointing it out though.