I'm considering building a FreeNAS box to replace a Synology DS1511 - mainly because I'd like it as a project with more flexibility.

Couple questions: 1. Most people recommend a hardware RAID controller - is it worth it that much over using software RAID? I'd be running ZFS, and probably RAID-5. 2. Which RAID type would allow me to swap a single drive for a larger one, and rebuild to that? I.e. so I can replace my 2TB drives with 4TB over time, as money allows.


  • My experience with real hardware RAID cards (not fake-raid) is they are substantially less reliable than software RAID. – ChrisInEdmonton Nov 6 '13 at 16:48
  • Funny you mention that, because last I had a hardware RAID, I lost everything! – Pat Nov 6 '13 at 18:50
  • If you want flexibility, I wouldn't recommend ZFS. There are a lot of limitations to expanding and upgrading drives. What you may want to look into is LVM. I wanted a zfs drobo-like box, and never found the perfect solution. If you want zfs, you will have to make trade-offs. – Scott McClenning Nov 7 '13 at 4:11
  1. For ZFS general recommendation is not to use hardware RAID controllers (or configure them in pass-through mode so that OS sees individual disks). ZFS takes care of redundancy and consistency checking.

  2. Alas ZFS is not that flexible. You may grow redundant zfs pool by replacing smaller drives in vdev with the larger ones one-by-one, but available space in the pool would only increase once all the drives in the vdev have been upgraded.

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