RAID1 to RAID0?

[hendry]

Hi! I think (can't tell in the UI!) my FreeNAS is in a RAID-1 configuration, which mean that 2x4TB is about 4TB. How do I turn RAID1 off, so I can reclaim back some storage space?

I don't need the level of RPO RAID1 gives me anymore, as I can afford to lose upto a day's worth of video footage because I usually have copies of the video footage elsewhere.. (it usually takes me a couple of days to format footage from SD cards)

https://s.natalian.org/2020-09-17/debug-freenas-20200917105400.tgz

I have a working daily Cloud Sync Task to backup my data off site to AWS with a relatively inexpensive Glacier Deep Archive. I calculated ~246USD for 2TB worst case retrieval cost. I've never needed it so far, hopefully I won't. And if I do, I'll probably just retrieve a couple of files, and not bother with a full restore.

I also find RAID1 a little worrying when IIUC, the drives have to be the same in the TrueNAS world here. I can't help but think if one drives fails, it's highly likely the other will too since it came from the same batch and had the same utilization IIUC.

 

[Heracles]

Hey @hendry,

The only was to drop your protection down to 0 is to destroy the pool and re-create it... Not recommended at all but do as you wish...

 

[hescominsoon]

the only way to go back is to backup all of the data..destroy the pool..and then rebuild. keep in mind a two drive raid 0 doubles your space but also doubles your failure potential..one drive dies everything is dead. In raid 1 if one drive fails you ahve the other..and unless the drives are acient the potential of a failure during a rebuild is quite low. If you want more space i would buy 2 8TB drives(make sure they are not smr drives)..then you offline the one drive. swap it out..onlie the new drive..the resilver will be quicker than you think. Once that's done replace the second drive and do the same thing..once they have both resilvered then extend the pool and you will have 8TB of space...

 

[HoneyBadger]

The only way to drop your protection down to 0 is to destroy the pool and re-create it... Not recommended at all but do as you wish...

the only way to go back is to backup all of the data..destroy the pool..and then rebuild.

You're right about it being a bad idea, but wrong about it being impossible.

Show : Here Be Dragons

From the CLI the command zpool detach poolname gptid/abcdefgh-1234-5678-9012-ijklmnopqrst should do the trick. There may also be an option in the GUI to offline and then detach a single drive from a mirror but I don't believe so.

 

[sretalla]

As hinted by @HoneyBadger , detach one of the disks from the mirror, then add it back by extending the pool and you will have what you're asking for.

The GUI supports that in 12, only CLI for users of 11.

 

[danb35]

IIUC, the drives have to be the same in the TrueNAS world here.

You do not understand correctly. If you need to replace a drive, the replacement only needs to be at least as large as the other disk in the pool. It can be a different manufacturer, different speed, different interface, whatever, doesn't matter, as long as it's at least as large as the other disk.

 

[hendry]

As hinted by @HoneyBadger , detach one of the disks from the mirror, then add it back by extending the pool and you will have what you're asking for.

The GUI supports that in 12, only CLI for users of 11.

Ok, maybe I should upgrade to 12 RC. But I don't quite understand. If I remove a disk and then add it back, surely it would just be re-incorporated back into the pool? Do I somehow need to initialize the disk?

I wish the UI would clearly tell me the RAID level I'm using. Does it in 12?

 

[jgreco]

Ok, maybe I should upgrade to 12 RC. But I don't quite understand. If I remove a disk and then add it back, surely it would just be re-incorporated back into the pool? Do I somehow need to initialize the disk?

I wish the UI would clearly tell me the RAID level I'm using. Does it in 12?

The UI does. Unfortunately, FreeNAS does not support "RAID" or "RAID levels". ZFS is a different technology. We use vdevs made out of two-or-more-way mirrors, or multiple disks in RAIDZ, which you might think is like RAID5 or 6, but is actually very different.

https://www.ixsystems.com/community/threads/terminology-and-abbreviations-primer.28174/

So when you look at your pool, under Storage / Pools / Pool Status, it will describe to you the composition of the pool.

 

[hendry]

So when you look at your pool, under Storage / Pools / Pool Status, it will describe to you the composition of the pool.

Whoa, quite hidden! Still I'm non-the-wiser what the composition is:

 

[jgreco]

It appears to be a simple mirror.

 

[Patrick M. Hausen]

So you can

1. detach one of the disks from your mirror leaving a single vdev comprised of a single disk
2. add that disk back to the pool as a separate vdev creating a pool of two striped vdevs

This will

1. double your storage space without loss of your current data
2. leave you without any redundancy - further if you lose one of the disks your entire pool is toast

If that is a good idea or not is not my concern here

If you post the output of zpool status in a code block I can send you the command to detach one of the disks. Adding it back as a new vdev can be done in the UI regardless of your FreeNAS version.

Alternatively you can add the free drive as another single drive pool. That way you have to manually manage which files you want to put where, but on the other hand you lose only one of the two pools when one drive fails. And for some files that you deem important you could even replicate a dataset to that other pool and have at least one backup copy of those files.

Pick your poison

HTH,
Patrick

 

[Arwen]

I second @Patrick M. Hausen's suggestion to create another single drive pool. It may be more management, but less risk. And less to restore when, (not if), one of the drives fails.


Wish their was a new ZFS vDev type, JBOD, where ZFS attempts to put any file on a single disk. (Plus, any updates to the file on the same disk.) Thus, if you loose a disk, you don't loose everything. And then don't have to restore everything. You don't get the speed of striping but, you don't loose everything. This method would even put any "copies=2", (or 3), on another disk. (Which actually includes the directory meta-data, which helps get the list of lost files on lost disk.)

This new vDev would be useful for just bulk storage.