ZFS Storage layout strategy with disks of unequal size

lifepillar

lifepillar

I've got a machine with one 1TB HD, and I have a spare 3TB HD. In the short-term, but not immediately, I plan to buy a 6–10TB HD, and in the medium-term I think to replace my current 3TB HD with another 6-10TB HD. I want to install FreeBSD with ZFS. What storage layout strategy do you recommend, given that I need some redundancy for all the data (maybe not immediately, but at least in the short-term)?

So far, I have tried the following:
  1. Install FreeBSD into the 1TB HD with Auto (ZFS) and striping;
  2. Boot into the new system and partition the 3TB HD into 1TB+2TB;
  3. Add the 1TB partition to the zroot pool, turning it into a mirror (not bootable from that partition, though—how to fix that?).
  4. Create a second striping pool out of the 2TB partition.
The idea is that, when I get another drive, I will be able to mirror the 2TB partition, too. Not sure how things can be rearranged, though, when I get the fourth drive. Ideally, I'd like to use the two drives with matching size as a mirror, and keep the 1TB HD only for the OS and unimportant stuff. Better ideas?
 
Mmh, in fact just two disks doesn't leave many options. Let's say I buy a 3+TB HDD instead. How about this:

Partitions:
  • [1TB HDD]: 1TB
  • [3TB HDD]: 1TB + 2TB
  • [3+TB HDD]: 1TB + 2TB + possibly empty space
Pools:
  • RAID-Z1: 1TB (across the three disks)
  • Mirror: 2TB (across disks 2 and 3)
Then, when I replace the 3TB HDD with a larger one, I can simply extend the mirror. Does it make sense? Is there anything I should be aware if I do something like this?

I've got the idea from: https://www.cod3r.com/2010/04/zfs-on-different-sized-disks/
 
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