Expand Raid 5 - New Install

[WallaceTech]

Guys.

I am looking to move over to FreeNAS from Unraid. I will be starting off with a 3 disk 500GB Raid 5 setup. I will then be looking to upgrade the discs and the Raid. I have searched the forums but I'm just not sure as some say yes and some say no.

1) Am i right in thinking that i can upgrade each of the discs one at a time, so say i have 3 500GB drives i can then one at a time upgrade to 1TB drives?

2) can i expand past 3 drives in my Raid 5?

Many thanks for any help you can give me with my setup.

 

[Brand]

If you are going to be using ZFS you won't be running a RAID5. You might want to do a little more reading about ZFS prior to embarking on this adventure. With RAIDZ you can replace each drive one at a time but will not benefit from it until all the drive have been replaced. Even in the most current version of ZFS you are not able to expand a RAIDZ by adding more disks to it.

 

[louisk]

What exactly do you mean by "expand"?

If you're using ZFS, you can replace smaller drives in a vdev with larger drives and it will grow the size of the vdev (once all drives have been upgraded).
If you're using ZFS, you can add vdevs to the pool on the fly to grow the size of the pool. You can't remove vdevs from the pool. Think carefully before you add vdevs to the pool.

 

[WallaceTech]

Thanks guys.

OK so the number of drives is quite critical then.

Is it possible to have 3 drives lets say Volume 1 then another set of 3 drives and lets call is Volume 2?

 

[b1ghen]

Thanks guys.

OK so the number of drives is quite critical then.

Is it possible to have 3 drives lets say Volume 1 then another set of 3 drives and lets call is Volume 2?

Yes, but you can actually start out with a pool consisting of just one 3 drive RAIDZ vdev, and then add (almost) an infinite amount of 3 drive RAIDZ vdevs to the same pool, this increases storage and also performance since data is striped across vdevs.
So no you can't expand with one drive at a time using ZFS.

Like the others said you can increase disk size one at a time and resilver after each drive and when the last one is completed you will gain the extra storage.

 

[WallaceTech]

ok so just to be clear if i want to keep adding drives i need to use RaidZ and vdev.

 

[louisk]

No. In order to add drives to an existing pool, you need to add them to a vdev. a pool can have >1 vdev, but you can't remove them later. Data redundancy is provided for at the vdev layer. You can have a pool with a raidz vdev, a mirror vdev, and a single drive vdev. In that example, you would have 1 spindle redundancy for both the raidz and the mirror, and the entire pool will fault if the single drive vdev fails.