Need help adding disks to my volume [FreeNas]

Hi Guys,

So without knowing much about FreeNas or storage in general I went ahead and built a NAS server. I could only afford one drive when I built the server and Im inpatient. I started using this single disk to store media.

Now I want to add two more disks giving me 3x 3TB. I would like some kind of protection against disk failure so after 10 minutes of research I concluded that RAIDz would best suit my requirements.

The issue is I am already using one of the disks and I don't have enough storage laying around to create a complete backup of it. I am pretty sure I will need to wipe it, create a new volume and kiss goodbye to most of my media collection. This data isn't critical so I guess its not the end of the world but if anyone here has a better plan Id love to hear it.

I did manage to add the two new disks to my volume but I don't think anyone would recommend my current configuration. I don't even understand it, would someone kindly explain what I did?

Finally, if I go ahead and wipe everything and create a new RAIDz volume, how do I increase storage in the future? Is this a simple process?

Thanks guys,


CPU + MB - ASRock c2750d4i

My current ZFS volume

I don't use freenas so I may be wrong but I'm pretty sure you can't add or remove disks from an array. If you create a RAIDz volume and want to add more storage to it latter you would create a second RAIDz volume and then join them, but you can't just add one disk at a time.

Once you create a volume or vdev in FreeNAS terms, like your 3x3TB RaidZ for example, the recommended way to increase the storage of that array is to extend a ZFS volume by creating a new 3x3TB RaidZ vdev and stipe it with the original vdev. The other option is to replace each 3TB drive (say with a 6TB drive), one at a time. FreeNAS will resilver the new drive from the redundant data each time a drive is replaced but the size of the vdev will not increase until you have replaced all the drives. My suggestion would be to buy a fourth drive to build your 3x3TB volume and then you can keep the original as a spare if one of the others die and you won't have to loose any data.

Most of this is covered in the FreeNAS documentation. Make sure you read through it carefully before making any more configuration decisions and before asking any questions on the FreeNAS forum. A few of the folks on there can get a little miffed when people ask questions without reading the documentation first. It's alright if you've read through but didn't understand some of it but be sure to clarify that when asking a question.

Thanks for breaking this down for me, I should probably give the documentation a once over!

Here's a link to the documents page:

The section on extending a ZFS volume is but the section that explains replacing drives for increasing size is 8.1.11.