How to reduce amount of disks in a freenas box?

[pern]

Hello,

I have a setup of 10tb with 4 x 3gb wd and red 2x 4tb in one dataset no jails or plugins

so this setup was expanded as time passed

setup 2 drives 3 tb as mirrored drives

then added 2 more 3tb drives as mirrored and subsequently a few years later added 2 red 4tb drives as mirror

so 3 different mirror setups

and now one 3 tb drive is bad and now I realized I have 4 tb free of storage, and since I am poor, I am considering just removing the bad 3 tb drive and also its companion 3tb mirrored drive.

how do I make sure which data is in which drive?

and make sure that the data is transferred to the free space?

 

[PhiloEpisteme]

Hi @pern

I have to admit, I don't fully understand your post entirely. Can you clarify a bit?

I have a setup of 10tb with 4 x 3gb wd and red 2x 4tb in one dataset no jails or plugins

Drives get arranged into vdevs, and vdevs are stripped to make pools. what is your vdev layout with these disks?

Consider my current build, I have two pools with vdevs as follows

Code:

pool0
  vdev0 - mirror 2x 3GB
  vdev1 - mirror 2x 3GB
  vdev2 - mirror 2x 3GB
pool1
  vdev0 - raidz2 6x 2GB

and now one 3 tb drive is bad and now I realized I have 4 tb free of storage, and since I am poor, I am considering just removing the bad 3 tb drive and also its companion 3tb mirrored drive.

how do I make sure which data is in which drive?

and make sure that the data is transferred to the free space?

Generally speaking you cannot do that, at least not how I think you are suggesting. FreeNAS uses zfs which exposes pools to use for storage. Pools are composed of one or more vdevs stripped together and vdevs are composed of disks in one of several configurations, single-drive, mirror, raidz1, raidz2, and raidz3. When you create a dataset in a pool and store data on it your data gets distributed across the underlying vdevs and therefore disks. It doesn't just fill up one and then move on to the next.

If I am understanding correctly I think your best bet would be to back up your data if you haven't already done so, then destroy and rebuild your entier pool in the configuration you prefer, and then restore from backup.

Do note that FreeNAS and redundant vdevs do not remove the need for backups. If something goes wrong with your pool you could lose everything. If you have 1 bad disk in that mirror vdev and the other goes bad before you replace them you will lose all of your data. Quality backups are important.

I hope this helps. If you wouldn't mind clarifying your exact setup it might help folks chime in with better advice or correct my advice if my understanding was not correct.

 

[SweetAndLow]

You can not remove disks in the way you want. You will have to backup your data and rebuild your pool. One think that is kind of nice is you can probably buy a single HDD large enough these days to put all your data on while you rebuild your pool.

 

[pern]

after doing some more reading, I understand your responses and I agree

to answer PhiloEpisteme:

I have 3 vdevs in 3 different mirrored setups all drives are running raid 1

after doing some thinking, I think I will end up just buying 2 8tb drives and destroy the pool and redo it

so if I do this, and install 2 8tb drives and create one pool, how do I back up this data from 3 different vdevs and put it in one pool?

 

[PhiloEpisteme]

I have 3 vdevs in 3 different mirrored setups all drives are running raid 1

Minor nit, but FreeNAS has no such thing as raid 1. I know what you mean, a mirrored vdev, but the distinction is important because freenas has a raidz1 which looks and reads a lot like raid 1 but is more like raid 5. But, thanks for the extra info; I think I got it now. You've got 1 pool, 3 vdevs, each is a mirror vdev of 2-disks.

so if I do this, and install 2 8tb drives and create one pool, how do I back up this data from 3 different vdevs and put it in one pool?

You can do this any number of ways. If you have the available ports and slots you can plug in the 8TB disks, build your pool, and then use zfs replication to move the data over. I think I would recommend this approach because it is fairly easy and will be quite fast if you're doing it on the same machine.