Hi, folks:
I'm new to FreeNAS. I want to build a server for my archive of home documents and photos. My top priority is to be robust against data loss. I don't demand much performance, and data efficiency is nice but secondary to robustness. My old server is a RAID1 with three 3TB drives rotating through two bays. My data has survived, but I know I've been lucky. I want to do better than that with FreeNAS. I currently store 2+ TB, but I will outgrow 3TB in a few months.
I have read a lot of the introduction resources. Thank you to everyone who took the time to write them. It's clear that I want RAID-Z2 instead of RAID-Z1, for robustness. I'm buying FreeNAS Mini hardware with 4 bays. I hear the importance of NAS-grade drives and ECC RAM loud and clear.
I have bought 3 x 10TB WD Red drives. It isn't clear to me if I can set them up as a 3-drive RAID-Z2 vdev. According to the concept of data + 2 parity, it should be possible, and result in a 10TB vdev with two parity. But guides seem to talk about 3-drive vdevs as RAID-Z1 only, and implies that one can only start considering RAID-Z2 with a minimum of 4 drives. What's the real situation? Where in the documentation are the actual constraints described?
The concrete options in front of me seem to be:
—Jim DeLaHunt, Vancouver, Canada
I'm new to FreeNAS. I want to build a server for my archive of home documents and photos. My top priority is to be robust against data loss. I don't demand much performance, and data efficiency is nice but secondary to robustness. My old server is a RAID1 with three 3TB drives rotating through two bays. My data has survived, but I know I've been lucky. I want to do better than that with FreeNAS. I currently store 2+ TB, but I will outgrow 3TB in a few months.
I have read a lot of the introduction resources. Thank you to everyone who took the time to write them. It's clear that I want RAID-Z2 instead of RAID-Z1, for robustness. I'm buying FreeNAS Mini hardware with 4 bays. I hear the importance of NAS-grade drives and ECC RAM loud and clear.
I have bought 3 x 10TB WD Red drives. It isn't clear to me if I can set them up as a 3-drive RAID-Z2 vdev. According to the concept of data + 2 parity, it should be possible, and result in a 10TB vdev with two parity. But guides seem to talk about 3-drive vdevs as RAID-Z1 only, and implies that one can only start considering RAID-Z2 with a minimum of 4 drives. What's the real situation? Where in the documentation are the actual constraints described?
The concrete options in front of me seem to be:
- Create a RAID-Z2 vdev with the 3 x 10TB drives. Expect 10 TB capacity. Don't expand it until I buy three larger drives, or buy a bigger case and create a second vdev, or until FreeNAS someday starts to allow adding drives to vdevs.
- Create a RAID-Z1 vdev with the 3 x 10TB drives. Expect 14 TB capacity. Manage the increased risk of data loss by a more disciplined backup strategy. Accept the same limitations against expanding as for #1.
- Buy a 4th drive. Create a RAID-Z2 vdev with the 4 x 10TB drives. Expect 14TB capacity. (But I'd be happy with 10TB, and option 1.)
- Buy a 4th drive. Create a RAID-Z3 vdev with the 4 x 10TB drives. Expect 10TB capacity. Celebrate the increased robustness against data loss.
- Create a RAID-Z1 vdev with the 2 x 10TB drives. Expect 10 TB capacity. Use the 3rd drive standalone for backups. (It seems like ZFS could put the drive to better use.)
—Jim DeLaHunt, Vancouver, Canada