Currently new to trueNAS and I’m planning to create a little home server with my old pc, just a little experiment, I currently have 1 x 2TB HDD for the data storage and 128gb SSD for boot, and planning to upgrade to 2 x 4TB HDD, Do I use CORE or SCALE?
It will be able to detect errors, but not correct them. And if you lose a disk, you’re obviously toast.
When you get the extra disks, you can firstly extend your current single disk vdev (the vdev, not the pool) with one of the new disks to add redundancy, and then you can replace the original 1TB disk with the other new disk, and then your vdev will resize, thus provided 4TB of space with 4TB of redundancy.
You can continue adding pairs of disks as additional vdevs if you chose, or continue to replace disks to grow capacity.
OR if you decide to change from mirrors to raidz (1,2,3), then you would pretty much want to adopt a new pool and transfer to it (which can be done locally)
For the sake of completeness: Even with one drive ZFS could still correct errors by setting copies=2 (of course, it costs half the space, and does not help with drive failure).
This is for like future reference, How about getting another 2TB drive and then add the other 4 TB drives and create them as 1 pool would that be equivalent to a 6 TB storage? Or do i need to have a pool for each like 2 x 2 TB and 2 x 4 TB
If I understand you correctly: 2x2TB and 2x4TB can be striped to give you 6 TB total. Remember once 4 TB are written (2TB of the smaller drives and 2 TB of the 4 TB drives) there’s 2 TB left that can only be written to the larger disk, so you will lose the performance advantage of a stripe in the end.