How can I add a disk without removing all data?

[luk]

Hello it is my first time making a NAS and I have successfully got TrueNAS running on my computer right now. In my computer I have a 500GB HDD which I would like to make visible to other devices on the network. Everything is completely new to me and I don't know where to start. I tried going to Storage → Pools → Add, and then create a new pool with the 500GB disk. However when I click "create" a prompt comes up saying "The contents of all added disks will be erased.", which I do not want. After that I tried going to Storage → Import Disk, but didn't understand much of how it worked. Is it not, possible to add a disk that already has existing data does creating a storage pool format the disk, why? Is my only option to backup all my other files to another disk, create the pool and then copy them back? What if I had a bigger disk, 12, 14, or even 20TB of data? It doesn't sound reasonable.

I also have two new 10TB disks that I plan to mirror, will I be available to increase the space, or upgrade to e.g raid 6 if I in the future purchase more drives?
I'm reading the documentations for answers and this "https://www.truenas.com/docs/hub/tasks/advanced/extendpool/" seems to answer the above questinon, however I'm not sure. I don't want to make the wrong decision now, that I will regret later in time because I rushed setting everything up correctly.

Thanks a lot!

 

[sretalla]

I also have two new 10TB disks that I plan to mirror, will I be available to increase the space, or upgrade to e.g raid 6 if I in the future purchase more drives?

Extending a pool is fine, but it won't change a pool with a mirrored VDEV into a pool with a RAIDZ2 VDEV. You should probably have a look at the ZFS primer material in the resources section, like this one: https://www.truenas.com/community/resources/introduction-to-zfs.111/

You can certainly add mirrored VDEVs to your heart's content to increase the capacity (and IOPS potential) of your pool, but your pool can't become a different type without a rebuild (backup, destroy, recreate, restore).

In my computer I have a 500GB HDD which I would like to make visible to other devices on the network. Everything is completely new to me and I don't know where to start. I tried going to Storage → Pools → Add, and then create a new pool with the 500GB disk. However when I click "create" a prompt comes up saying "The contents of all added disks will be erased.", which I do not want. After that I tried going to Storage → Import Disk, but didn't understand much of how it worked. Is it not, possible to add a disk that already has existing data does creating a storage pool format the disk, why? Is my only option to backup all my other files to another disk, create the pool and then copy them back? What if I had a bigger disk, 12, 14, or even 20TB of data? It doesn't sound reasonable.

What filesystem is on that disk?

If it isn't ZFS, you have the option to "import" the disk (applies to some filesystems), but it needs to import the contents to a pool (which will be ZFS) which is by necessity already there in the system, and isn't an in-place change as the filesystem is different.

If it is ZFS, just import the pool.