Increasing hard drive capacity question

[NASbeginner]

Hi guys,

I think I've settled on FreeNAS for my first NAS build. It has been great reading through this forum. However, before I get started, I wanted to make sure I understand how I can increase my HDD capacity once the RaidZ2 is setup.

For instance if I started with 6 4TB drives and then someday I want to increase capacity, can I simply swap out the 6 4TB drives for 6 6TB, etc. within the vdev? If so, the question is how difficult is it to do?

 

[mattbbpl]

Yes you can. You'll just have to do so one at a time so the drives can resilver. You won't see any additional capacity until every single one of the drives are upgraded, though.

 

[solarisguy]

@NASbeginner, user [B]Bidule0hm[/B] has developed a tool http://biduleohm.free.fr/zfsraidsarc/ for calculating usable space on ZFS pools. You should try it, to learn how much disk space you can really use for any given number of disks, depending on their size.

Why? I am finding that very often the useful upgrades are the ones that double the usable storage space...

Try RAID-Z2 with disks that are 4TB, 6TB or 8TB. Try RAID-Z2 with either 6 or 8 disks. Look at the line Usable data space with the value shown in TiB

 

[NASbeginner]

Thanks guys. I guess it's better cost wise to add a new vdev and not replace 4TB with 6, or 8TB later...

 

[danb35]

I guess it's better cost wise to add a new vdev and not replace 4TB with 6, or 8TB later

That usually is better, supposing your system can support the additional drives.

 

[solarisguy]

For home users, either SOHO or fun or just a family storage, I tend to recommend minimizing number of physical disks.

Yes, I know it is a trade-off between the cost, but not convenience, it is a trade-off between the cost and ability of an average home user to take care of / administer large systems. A single "PC", even with 8-10 drives inside, is not the same as a behemoth that requires special considerations for cooling and noise.